Note: This page contains sample records for the topic 2 20 kev range from Science.gov.
While these samples are representative of the content of Science.gov,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of Science.gov
to obtain the most current and comprehensive results.
Last update: November 12, 2013.
1

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

PubMed

The X-ray optics group at the Swiss Light Source in co-operation with RIT (Rigaku Innovative Technologies) have investigated seven different multilayer samples. The goal was to find an ideal multilayer structure for the energy range between 6?keV and 20?keV in terms of energy resolution and reflectivity. Such multilayer structures deposited on substrates can be used as X-ray monochromators or reflecting synchrotron mirrors. The measured reflectivities agree with the simulated ones. They cover a reflectivity range from 45% to 80% for energies between 6?keV and 10?keV, and 80% to 90% for energies between 10?keV and 20?keV. The experimentally measured energy resolution of the samples lies between 0.3% and 3.5%. PMID:22898944

Oberta, P; Platonov, Y; Flechsig, U

2012-08-03

2

A direct comparison of Ge and Si(Li) detectors in the 2--20 keV range  

SciTech Connect

The spectral response of high purity Ge (HPGe) and lithium-drifted Si (Si(Li)) surface barrier detectors of similar geometry has been measured over a range of x-ray energies under identical experimental conditions. Detector characteristics such as spectral background, escape peak intensity, entrance window absorption, and energy resolution are presented and compared. Although these characteristic have been discussed in the literature previously, this paper represents an attempt to consolidate the information by making comparisons under equivalent experimental conditions for the two types of detectors. A primary goal of the study is a comparison of the two types of detectors for use in x-ray fluorescence applications.

Rossington, C.S.; Giauque, R.D.; Jaklevic, J.M.

1991-10-01

3

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

NASA Astrophysics Data System (ADS)

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.

Moldovan, G.; Sikharulidze, I.; Matheson, J.; Derbyshire, G.; Kirkland, A. I.; Abrahams, J. P.

2012-07-01

4

Complete polarization analysis in the 1keV to 2keV energy range using a high-precision polarimeter  

NASA Astrophysics Data System (ADS)

The Beryl and YB66 crystals are proved to be suitable as analyzers in the energy range from 1.0keV to 2.0keV. The s-component reflectivity (Rs) of Beryl crystal reaches up to 10% with polarizing power Rs/Rp over 1000 at 1.1keV. The free-standing W/B4C multilayer has the phase shift over 5 with moderate transmission up to 1.7keV. The Bragg resonance width of the Beryl crystal is only 350 microradians at 1.1keV, and the incidence angle of the beam onto the crystal needs to be constant within 50 microradians or better. A high-precision polarimeter was used for the polarimetry experiment, and the complete polarization analysis of the APPLE II undulator at 1.1 keV and 1.56keV will be presented.

Wang, Hongchang; Dhesi, Sarnjeet; Bencok, Peter; Steadman, Paul; Maccherozzi, Francesco; Sawhney, Kawal

2013-03-01

5

A Study of 2-20 Kev X-Rays from the Cygnus Region.  

National Technical Information Service (NTIS)

Two rocket-borne proportional counters, each with 650 sqen1 c, met area and 1.8 x 7.1 deg FWHM rectangular mechanical collimation, surveyed the Cygnus region in the 2 to 20 keV energy range on two occasions. X-ray spectral data gathered on 21 September 19...

R. D. Bleach

1972-01-01

6

Sputtering yields, range and range straggling in Al following Kr+ ions bombardment in the energy range (20 160) keV  

NASA Astrophysics Data System (ADS)

The sputtering of Al metallic films by 84Kr+ ions has been studied over the energy range (20 160) keV. Sputtering yield data have been extracted by means of the Rutherford backscattering technique (RBS) using a 2 MeV beam of 4He+ ions. They have been compared to values derived by Sigmunds linear cascade theory, Yamamuras semi-empirical formula or by Monte Carlo computer simulation using the TRIM code. A fair agreement was observed between the measured sputtering yields and the predicted ones. The depth profiles of the implanted Kr+ ions into Al have also been measured, and then fitted assuming Gaussian shape distributions, which allowed us to extract the projected range, Rp, and the associated range straggling, ?Rp. For the former stopping parameter, a very good agreement is obtained between experiment and the LSS theory predictions while the MC simulation also accounts satisfactorily for the measured data over the whole explored energy range, reflecting an adequate description of the projectile-target interaction by the universal potential of the Thomas Fermi type assumed in the LSS formalism. In contrast, the ?Rp measured data show to be consistent with the predicted values only at E ? 60 keV but lie to 30% above them at lower energies. This discrepancy not caused by the sputtering effect relates to an incomplete evaluation of the range straggling by theory at low bombarding energies.

Mammeri, S.; Ouichaoui, S.; Zemih, R.; Ammi, H.; Abdesselam, M.; Chami, A. C.

2005-10-01

7

Hydrogen. Stopping powers and ranges in all elements. [10 keV to 20 MeV (per amu); book  

Microsoft Academic Search

Absolute experimental energy-loss data for hydrogen are presented over the energy range E\\/amu = 10 keV to 20 MeV. Data were fitted to analytical functions, the parameters of which are given together with the experimental data. An attempt was made to interpolate the fitting parameters to elements for which there are no experimental data. Fitted stopping powers were integrated to

H. H. Andersen; J. F. Ziegler

1977-01-01

8

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

NASA Astrophysics Data System (ADS)

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.

Moldovan, G.; Matheson, J.; Derbyshire, G.; Kirkland, A.

2008-11-01

9

Characterisation of a monolithic active pixel sensor for electron detection in the energy range 10-20 keV  

NASA Astrophysics Data System (ADS)

As part of a feasibility study into the use of novel electron detectors for X-ray photoelectron emission microscopes (XPEEM), we have characterised the imaging performance of a back-illuminated monolithic active pixel sensor (MAPS) operating under both integrating and counting modes for electrons in the energy range 10-20 keV. For integrating mode, we present the detective quantum efficiency (DQE), which shows marked improvements over conventional indirect detectors based on microchannel plates. We also present the modulation transfer function (MTF) and noise power spectrum (NPS), again demonstrating significantly improved performance. For counting mode, we present the quantum efficiency (QE) as a function of incident electron energy. We have evaluated the charge collection efficiency (CCE) and we thereby demonstrate the presence of a ~200 nm thick dead layer that is linked with reduced CCE at low electron energies. Based on our findings, we believe that the MAPS technology is well matched to future XPEEM instruments using aberration correction.

Matheson, J.; Moldovan, G.; Clark, A.; Prydderch, M.; Turchetta, R.; Derbyshire, G.; Kirkland, A.; Allinson, N.

2009-09-01

10

Absolyutnaya spektral'naya chuvstvitel'nost' fotodiodnykh lineek v rentgenovskom diapazone 7-20 kehV. (Absolute spectral sensitivity of photodiode arrays in the X-ray energy range 7-20 keV).  

National Technical Information Service (NTIS)

The results of the investigation of absolute spectral sensitivity of linear photodiode arrays (the kind LF1024-25/2) as X-ray one-coordinate detectors in the energy range from 7 to 20 keV are presented. The measurements have been carried out with the use ...

I. P. Dolbnya S. G. Kurylo

1991-01-01

11

Measuring the absolute sensitivity of an X-ray electron-optical image converter in the range 7-20 keV  

Microsoft Academic Search

The absolute sensitivity of an X-ray electron-optical image converter with a MCP used as both photocathode and amplifier has been investigated using synchrotron radiation from the VEPP-3 storage ring (INP, Novosibirsk) in the energy range of 7 to 20 keV. In this spectral range the response of the converter increases from 1200 to 2200 blue photons at the output per

I. P. Dolbnya; B. A. Knyazev; V. P. Simonov; G. G. Feldman

1991-01-01

12

Extragalactic X-ray Background in the 0.2-2 keV Range.  

National Technical Information Service (NTIS)

We made the first measurement of the extragalactic 0.7 keV background. We detected the X-ray shadow of a neutral gas cloud in the Magellanic Bridge. We further constrained the point-like source contribution based on the mean spectrum of detected sources a...

D. Q. Wang

1997-01-01

13

Testing of typical spacecraft materials in a simulated substorm environment. [1 nA\\/cm² of 2- to 20keV electrons  

Microsoft Academic Search

An investigation to determine spacecraft materials characteristics under charging conditions was conducted at the Lewis Research Center substorm simulation facility. The test specimens were spacecraft paints, silvered Teflon, thermal blankets and solar array segments. The samples, ranging in size from 300 to 1,000 sq cm were exposed to monoenergetic electron energies from 2 to 20 keV at a current density

N. J. Stephens; F. D. Berkopec; J. V. Staskus; R. A. Blech; S. J. Narciso

1976-01-01

14

X-ray-sensitive device based on a linear CCD for recording the radiation in the energy range 0.20 to 40.00 keV  

Microsoft Academic Search

The C(Pi) M11 x-ray sensitive device is intended for recording the one-dimensional space distribution of x-radiation fluence in the spectral energy range from 0.2 to 40.0 keV and can be used as a part of x-ray spectrometers of different types instead of the photographic film and for measurement of spatial parameters of x-ray beams and oth.

B. F. Voronov; M. V. Emelyanov; Yu. I. Kozhunov; O. B. Kozlov; S. I. Rybin; A. E. Favorski

1999-01-01

15

Neutron Scattering Cross Sections for Natural Carbon in the Energy Range 2-133 keV  

SciTech Connect

Natural carbon is well known as reactor structure material and at the same time as one of the most important neutron scattering standards, especially at energies less than 2 MeV, where the neutron total and neutron scattering cross sections are essentially identical. The best neutron total cross section experimental data for natural carbon in the range 1-500 keV have uncertainties of 1-4%. However, the difference between these data and those based on R-matrix analysis and used in the ENDF libraries is evident, especially in the energy range 1-60 keV. Experimental data for total scattering neutron cross sections for this element in the energy range 1-200 keV are scanty. The use of the technique of neutron filtered beams developed at the Kyiv Research Reactor makes it possible to reduce the uncertainty of the experimental data and to measure the neutron scattering cross sections on natural carbon in the energy range 2-149 keV with accuracies of 3-6%. Investigations of the neutron scattering cross section on carbon were carried out using 5 filters with energies 2, 3.5, 24, 54 and 133 keV. The neutron scattering cross sections were measured using a detector system covering nearly 2{pi}. The detector consisting of {sup 3}He counters (58 units), was located just above the carbon samples. The {sup 3}He counters (CHM-37, 7 atm, diameter =18 mm, L=50 cm) are placed in five layers (12 or 11 in each layer). To determine the neutron scattering cross section on carbon the relative method of measurement was used. The isotope {sup 208}Pb was used as the standard. The normalization factor, which is a function of detector efficiency, thickness of the carbon samples, thickness of the {sup 208}Pb sample, geometry, etc., for each sample and for each filter energy has been obtained through Monte Carlo calculations by means of the MCNP4C code. The results of measurements of the neutron scattering cross sections at reactor neutron filtered beams with energies in the range 2-133 keV on carbon samples together with the known experimental data from database EXFOR/CSISRS and ENDF libraries are presented.

Gritzay, O; Gnidak, M; Kolotyi, V; Korol, O; Razbudey, V; Venedyktov, V; Richardson, J H; Sale, K

2006-06-14

16

A silicon <111> phase retarder for producing circularly polarized x-rays in the 2.1-3 keV energy range  

NASA Astrophysics Data System (ADS)

Circularly polarized synchrotron light is routinely used to study different material properties but is difficult to generate reproducibly below 3.1 keV. We present data from a 5 ?m Si <111> phase retarder (PR) designed to operate in the 2.1 to 3 keV energy range. Measurements were performed at the Pd L3 edge to enable direct comparison with a conventional diamond PR. The degree of circular polarization was ascertained indirectly by recording the resonant specular reflectivity from a [Fe(2 ML)/Pd(15 ML)]20 multilayer. Our findings show that such a device can be used to extend the usable energy capability of PR technology down to 2.1 keV.

Bouchenoire, Laurence; Morris, Richard J. H.; Hase, Thomas P. A.

2012-08-01

17

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  

SciTech Connect

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.

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

2000-05-01

18

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

SciTech Connect

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.

Jourdain, E.; Roques, J. P.; Malzac, J. [Universite de Toulouse, UPS-OMP, IRAP, Toulouse (France)

2012-01-01

19

The Emission of Cygnus X-1: Observations with INTEGRAL SPI from 20 keV to 2 MeV  

NASA Astrophysics Data System (ADS)

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. Based on observations with INTEGRAL, an ESA project with instruments and science data centre funded by ESA member states (especially the PI countries: Denmark, France, Germany, Italy, Spain, and Switzerland), Czech Republic and Poland with participation of Russia and USA.

Jourdain, E.; Roques, J. P.; Malzac, J.

2012-01-01

20

Angular distribution of thick-target bremsstrahlung produced by electrons with initial energies ranging from 10 to 20 keV incident on Ag  

SciTech Connect

Experimental results are presented comparing the intensities of the bremsstrahlung produced by electrons with initial energies ranging from 10 to 20 keV incident on a thick Ag target, measured at forward angles in the range of 0 degree sign to 55 degree sign . When the data are corrected for attenuation due to photon absorption within the target, the results indicate that the detected radiation is distributed anisotropically only at photon energies k that are approximately equal to the initial energy of the incident electrons E{sub 0}. The results of our experiments suggest that, as k/E{sub 0}{yields} 0, the detected radiation essentially becomes isotropic due primarily to the scattering of electrons within the target. A comparison to the theory of Kissel et al.[At. Data Nucl. Data Tables 28, 381 (1983)] suggests that the angular distribution of bremsstrahlung emitted by electrons incident on thick targets is similar to the angular distribution of bremsstrahlung emitted by electrons incident on free-atom targets only when k/E{sub 0}{approx_equal} 1. The experimental data also are in approximate agreement with the angular distribution predictions of the Monte Carlo program penelope.

Gonzales, D.; Cavness, B.; Williams, S. [Department of Physics, Angelo State University, San Angelo, Texas 76909 (United States)

2011-11-15

21

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  

SciTech Connect

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.

Derrien, H

2005-12-05

22

Effective atomic numbers for photon energy absorption of essential amino acids in the energy range 1 keV to 20 MeV  

Microsoft Academic Search

Effective atomic numbers for photon energy-absorption (ZPEAeff) of essential amino acids histidine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine have been calculated by a direct method in the energy region of 1keV to 20MeV. The ZPEAeff values have been found to change with energy and composition of the amino acids. The variations of mass energy-absorption coefficient, effective atomic number

S. R. Manohara; S. M. Hanagodimath

2007-01-01

23

plutonium isotopic analysis in the 30 KeV to 210 KeV range  

SciTech Connect

Low-Energy Gamma-ray Spectroscopy (LEGS) is a nondestructive assay (NDA) technique developed in the 1980s. In 1999, it was modified to include a physical-based model for the energy dependent efficiency. It uses the gamma rays in the energy range from approximately 30 keV to 210 keV, except the 100-keV region. This energy region provides intense, well-separated gamma rays from the principal isotopes of plutonium. For applications involving small quantities (mg to g) of freshly separated plutonium in various chemical forms, it is ideally suited for accurate real-time or near real-time isotopic analysis. Since the last modification, LEGS has been incorporated into the FRAM code (Fixed-energy Response-function Analysis with Multiple efficiency), version 4. FRAM v4 is capable of analyzing the peaks in the whole energy range from 30 keV to 1 MeV, including the X-ray region. The new capability of analyzing the peaks in the 100-keV region greatly enhances the plutonium analysis in the 30 keV to 2 10 keV ranges of the traditional LEGS. We now can analyze both the freshly separated and aged plutonium with greater accuracy.

Vo, Duc T.; Li, T. K. (Tien K.)

2001-01-01

24

(239)Pu neutron resonance parameters revisited and covariance matrix in the neutron energy range from thermal to 2.5 keV  

SciTech Connect

To obtain the resonance parameters in a single energy range up to 2.5 keV neutron energy and the corresponding covariance matrix, a reevaluation of 239Pu was performed with the analysis code SAMMY. The most recent experimental data were analyzed in the energy range thermal to 2.5 keV. The experimental data were renormalized, aligned on a common energy scale, and corrected for residual background. Average neutron transmission and cross sections calculated with the new resonance parameters were compared to the corresponding experimental data and to ENDF/B-VI.

Derrien, Herve [ORNL; Leal, Luiz C [ORNL; Larson, Nancy M [ORNL

2008-01-01

25

Absolute Cross Sections for Excitation of Neon by Impact of 20-180keV H+, H+2, and He+  

Microsoft Academic Search

The technique of heavy-ion energy-loss spectrometry has been used to measure excitation cross sections for the (2p5)3s and (2p5)3p electronic configurations of neon by impact of heavy ions upon ground-state neon. The incident particles used were H+, H+2, and He+ at impact energies from 20 to 180 keV. The results are compared with previous optical measurements of the emission cross

G. W. York; J. T. Park; V. Pol; D. H. Crandall

1972-01-01

26

Development of a soft x-ray diffractometer for a wideband multilayer grating with a novel layer structure in the 2-4 keV range  

NASA Astrophysics Data System (ADS)

We have been developing a wavelength-dispersive soft x-ray spectrograph covering an energy region of 50-4000 eV to attach to a conventional electron microscope. Observation of soft x-ray emission in the 2-4 keV range needs a multilayer coated grating. In order to evaluate the performance of the optical component in the energy region, a goniometric apparatus has been newly developed and the preliminary performance has been tested using synchrotron radiation.

Imazono, Takashi; Koike, Masato; Kawachi, Tetsuya; Hasegawa, Noboru; Koeda, Masaru; Nagano, Tetsuya; Sasai, Hiroyuki; Oue, Yuki; Yonezawa, Zeno; Kuramoto, Satoshi; Terauchi, Masami; Takahashi, Hideyuki; Handa, Nobuo; Murano, Takanori

2012-07-01

27

Transmission and Self-Indication Measurements with U-235 and Pu239 in the 2 eV20 keV Energy Region  

Microsoft Academic Search

The transmission and self-indication measurements with U-235 and Pu-239 have been carried out using the ³He proportional counter and fission chambers in the 2 eV-20 keV energy region. The TOF technique was used with JINR pulse fast reactor IBR-30 in Dubna as a neutron source, the resolution being 100 nsec\\/m (³He counter measurements) and 53 nsec\\/m (fission chamber measurements). The

T. Bakalov; G. Ilchev; S. Toshkov; Tran Khanh Mai; N. Janeva; A. A. van'kov; Yu. V. Grigoriev; V. F. Ukraintsev

1980-01-01

28

Determination of the dependence of HPGe virtual point detector location on source dimensions in 60 keV-2 MeV range using Monte Carlo simulation  

NASA Astrophysics Data System (ADS)

The virtual point detector (VPD) concept for an HPGe detector with 55% relative efficiency was confirmed for bulky sources having different diameters and heights. After reproducing experimental data, Monte Carlo simulation was used to investigate the dependence of VPD location on photon energy for various source diameters and heights in the energy range from 60 keV to 2 MeV. The simulations were confirmed using a soil reference source prepared by International Atomic Energy Agency (IAEA). It was seen that increasing photon energy makes significant changes in VPD location up to 600 keV. It was observed that VPD locations increase with increasing source diameter and height. It was also seen that VPD locations were approximately linearly dependent on source diameters and heights.

elik, N.

2012-08-01

29

Transmission and self-indication measurements with U-235 and Pu-239 in the 2 eV-20 keV energy region  

SciTech Connect

The transmission and self-indication measurements with U-235 and Pu-239 have been carried out using the /sup 3/He proportional counter and fission chambers in the 2 eV-20 keV energy region. The TOF technique was used with JINR pulse fast reactor IBR-30 in Dubna as a neutron source, the resolution being 100 nsec/m (/sup 3/He counter measurements) and 53 nsec/m (fission chamber measurements). The sample thickness was varied from 0.0013 atom/barns to 0.172 atom/barns. Average total cross sections with self shielding factors and self-shielding fission factors were determined for energies within ABBN nuclear constant set.

Bakalov, T. (Joint Inst. for Nuclear Research, Dubna, USSR); Ilchev, G.; Toshkov, S.; Mai, T.K.; Janeva, N.; Van'kov, A.A.; Grigoriev, Yu.V.; Ukraintsev, V.F.

1980-09-01

30

An in-vacuum x-ray diffraction microscope for use in the 0.7-2.9 keV range.  

PubMed

A dedicated in-vacuum coherent x-ray diffraction microscope was installed at the 2-ID-B beamline of the Advanced Photon Source for use with 0.7-2.9 keV x-rays. The instrument can accommodate three common implementations of diffractive imaging; plane wave illumination; defocused-probe (Fresnel diffractive imaging) and scanning (ptychography) using either a pinhole, focused or defocused probe. The microscope design includes active feedback to limit motion of the optics with respect to the sample. Upper bounds on the relative optics-to-sample displacement have been measured to be 5.8 nm(v) and 4.4 nm(h) rms/h using capacitance micrometry and 27 nm/h using x-ray point projection imaging. The stability of the measurement platform and in-vacuum operation allows for long exposure times, high signal-to-noise and large dynamic range two-dimensional intensity measurements to be acquired. Finally, we illustrate the microscope's stability with a recent experimental result. PMID:22462925

Vine, D J; Williams, G J; Clark, J N; Putkunz, C T; Pfeifer, M A; Legnini, D; Roehrig, C; Wrobel, E; Huwald, E; van Riessen, G; Abbey, B; Beetz, T; Irwin, J; Feser, M; Hornberger, B; McNulty, I; Nugent, K A; Peele, A G

2012-03-01

31

An in-vacuum x-ray diffraction microscope for use in the 0.7-2.9 keV range  

SciTech Connect

A dedicated in-vacuum coherent x-ray diffraction microscope was installed at the 2-ID-B beamline of the Advanced Photon Source for use with 0.7-2.9 keV x-rays. The instrument can accommodate three common implementations of diffractive imaging; plane wave illumination; defocused-probe (Fresnel diffractive imaging) and scanning (ptychography) using either a pinhole, focused or defocused probe. The microscope design includes active feedback to limit motion of the optics with respect to the sample. Upper bounds on the relative optics-to-sample displacement have been measured to be 5.8 nm(v) and 4.4 nm(h) rms/h using capacitance micrometry and 27 nm/h using x-ray point projection imaging. The stability of the measurement platform and in-vacuum operation allows for long exposure times, high signal-to-noise and large dynamic range two-dimensional intensity measurements to be acquired. Finally, we illustrate the microscope's stability with a recent experimental result.

Vine, D. J. [Australian Research Council Centre of Excellence for Coherent X-ray Science (Australia); School of Physics, University of Melbourne, Victoria 3010 (Australia); Argonne National Laboratory, Argonne, Illinois 60439 (United States); Williams, G. J. [Australian Research Council Centre of Excellence for Coherent X-ray Science (Australia); SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Clark, J. N. [Australian Research Council Centre of Excellence for Coherent X-ray Science (Australia); Department of Physics, La Trobe University, Bundoora, Victoria 3086 (Australia); London Centre for Nanotechnology, University College, London WC1E 6BT (United Kingdom); Putkunz, C. T.; Abbey, B.; Nugent, K. A. [Australian Research Council Centre of Excellence for Coherent X-ray Science (Australia); School of Physics, University of Melbourne, Victoria 3010 (Australia); Pfeifer, M. A. [Australian Research Council Centre of Excellence for Coherent X-ray Science (Australia); Cornell High Energy Synchrotron Source, Cornell University, Ithaca, New York 14850 (United States); Legnini, D.; Roehrig, C.; Wrobel, E.; McNulty, I. [Argonne National Laboratory, Argonne, Illinois 60439 (United States); Huwald, E. [Department of Physics, La Trobe University, Bundoora, Victoria 3086 (Australia); Riessen, G. van; Peele, A. G. [Australian Research Council Centre of Excellence for Coherent X-ray Science (Australia); Department of Physics, La Trobe University, Bundoora, Victoria 3086 (Australia); Beetz, T.; Irwin, J.; Feser, M.; Hornberger, B. [Xradia, Inc., 4385 Hopyard Road, Pleasanton, California 94588 (United States)

2012-03-15

32

CCD imaging from 20 eV to 8 keV  

SciTech Connect

Pulsed x-ray diagnostics operating in the kilovolt and sub-kilovolt regimes are required in the study of x-ray laser schemes. Sensitivity and dynamic range measurements are presented for position-sensitive detector systems, designed and optimized for these spectral regions. Both systems employ cooled, multi-pinned phase CCD's for image capture. For photon energies from 20 eV to 1 keV (where direct detection with front illuminated devices is inadequate), a phosphor transducer is used, coupled to the CCD via a fiber optic faceplate with 6 {mu}m diameter channels. From 800 eV to 8 keV, direct detection of electron-hole pairs generated in the depletion region of the CCD is employed. The systems have been tested with single-shot sensitivity using a 10 Hz, 2J/7{center_dot}5 ns injection seeded Nd:YAG laser operated at 2{omega}, using Bragg crystal and flat field grazing incidence spectrometers to monitor the resonance emission from aluminium and carbon targets irradiated at {approx}10{sup 12} W cm{sup -2}. At 182 A, the sensitivity and dynamic range are enhanced with respect to that for a standard photographic detector, by factors of 8 and 300 respectively. An absolute calibration of the 700 eV-8 keV detector system performed at 1.6 keV, has been shown to agree with a calculation of sensitivity based on photo-absorption data. For this system, the enhancement in sensitivity and dynamic range over direct exposure x-ray film is 175 and 43 respectively.

MacPhee, A. G.; Lewis, C. L. S. [Department of Pure and Applied Physics, The Queens University of Belfast, BT7 1NN, Northern Ireland (United Kingdom)

1995-05-01

33

Electron impact calculations of total elastic cross sections over a wide energy range - 0.01 eV to 2 keV for CH4, SiH4 and H2O  

NASA Astrophysics Data System (ADS)

In this paper we report the results of a new theoretical methodology for determining the total elastic electron scattering cross section, Q el , over a wide range of incident energies between 0.01 eV and 2 keV. We have combined results from the UK molecular R-matrix code using Quantemol-N software to determine Q el for incident energies between 0.01 eV and the ionization threshold of the target with calculations based on the spherical complex optical potential formalism for higher energies up to 2 keV. We present results for three selected molecular targets; CH4, SiH4 and H2O as exemplars of the methodology. The present results were found to be in good agreement with previous experimental and theoretical results. The total elastic cross sections for such a wide energy range are reported perhaps for the first time.

Vinodkumar, M.; Limbachiya, C. G.; Joshipura, K. N.; Mason, N. J.

2011-02-01

34

Energy dependence of effective atomic numbers for photon energy absorption and photon interaction: studies of some biological molecules in the energy range 1 keV-20 MeV.  

PubMed

Effective atomic numbers for photon energy absorption, Z(PEA,eff), and for photon interaction, Z(PI,eff), have been calculated by a direct method in the photon-energy region from 1 keV to 20 MeV for biological molecules, such as fatty acids (lauric, myristic, palmitic, stearic, oleic, linoleic, linolenic, arachidonic, and arachidic acids), nucleotide bases (adenine, guanine, cytosine, uracil, and thymine), and carbohydrates (glucose, sucrose, raffinose, and starch). The Z(PEA,eff) and Z(PI,eff) values have been found to change with energy and composition of the biological molecules. The energy dependence of the mass attenuation coefficient, Z(PEA,eff), and the mass energy-absorption coefficient, Z(PI,eff), is shown graphically and in tabular form. Significant differences of 17%-38% between Z(PI,eff) and Z(PEA,eff) occur in the energy region 5-100 keV. The reasons for these differences, and for using Z(PEA,eff) rather than Z(PI,eff) in calculations of the absorbed dose, are discussed. PMID:18293593

Manohara, S R; Hanagodimath, S M; Gerward, L

2008-01-01

35

Incoherent scattering functions of iron, copper, zirconium, tin, tantalum, tungsten, gold and lead, in the momentum range 2 -1 ? q ? 46 -1 at 661.6 keV photon energy  

NASA Astrophysics Data System (ADS)

The incoherent scattering functions were calculated from the measured differential incoherent scattering cross sections for 661.6 keV photons with a hyper pure germanium detector in the angular range of 5 120 covering the momentum range 2 -1 ? q ? 46 -1 for iron, copper, zirconium, tin, tantalum, tungsten, gold and lead. The measured incoherent scattering functions were compared with the NRHF values, recent DHFR values and other measured values.

Krishnaveni, S.; Gowda, Ramakrishna

2005-04-01

36

Forecasting the arrival of fast coronal mass ejecta at Earth by the detection of 2-20 keV neutral atoms  

NASA Astrophysics Data System (ADS)

Studies have shown that Earth passages of fast coronal mass ejections (CMEs) trigger geomagnetic storms. Early identification of fast earth-directed CME can help provide storm warnings, but detection of such by coronagraphs is extremely difficult. We suggest that energetic hydrogen atoms (EHA) between 2 and 10 keV produced during the transit phase of an Earth-directed CME by recombination between protons and electrons in the CME can travel ahead of the CME and act as harbingers of a magnetic storm. This forecasting scheme should work if enough EHA are produced, because while CMEs decelerate continuously after their ejection, the EHA fluxes produced in the initial phase of fast CMEs propagate at their initial high speeds. Model simulations support this proposed mechanism.

Hsieh, K. C.; Shih, K. L.; McComas, D. J.; Wu, S. T.; Wu, C. C.

37

Formula for the total stopping power from 2 keV to 10 keV for a metal  

NASA Astrophysics Data System (ADS)

On the basis of the range-energy relationship, the relationships ( L 2-10) among the total stopping power from 2 keV to 10 keV for a metal ( S 2-10), the energy exponent ( n 2-10), the primary energy at the surface ( W p0), and the parameter ( A 2-10) were deduced. In addition, the relationships ( L 10-30) among the total stopping power from 10 keV to 30 keV for a metal ( S 10-30), the energy exponent ( n 10-30), W p0 and the parameter ( A 10-30) were obtained. According to some relationships between the parameters of the secondary electron yield from 2 keV to 10 keV for a metal ( ? 2-10), the composition of the secondary electron yield from 10 keV to 30 keV for a metal ( ? 10-30), L 2-10, and L 10-30, the universal formula for expressing S 2-10 as a function of S 10-30, ? 2-10, ? 10-30, the backscattered coefficient ( ?) from 2 keV to 10 keV, ? from 10 keV to 30 keV and W p0 was deduced. The S 2-10 calculated from this universal formula and the S 2-10 measured experimentally were compared, and we conclude that the formula presented in this paper is universal for S 2-10.

Xie, Ai-Gen; Lai, Min; Zhang, Chen-Yi

2013-01-01

38

Calculation of H-ranges and H-range stragglings in the energy region 11000 keV  

Microsoft Academic Search

The use of various approximations in calculating proton projected ranges has been studied by the analytical and the Monte Carlo methods. A correction is presented for the projected ranges given in the compilation (Andersen and Ziegler: Hydrogen Stopping Powers and Ranges in All Elements). The greatest correction factors at 1, 10, 100 and 1000 keV are 3.5, 2.1, 1.4 and

A. Luukkainen; M. Hautala

1982-01-01

39

Forecasting the arrival of fast coronal-mass ejecta at Earth by the detection of 2-20keV neutral atoms  

NASA Astrophysics Data System (ADS)

Studies have show that Earth passages of fast coronal mass ejections (CMEs) trigger geomagnetic storms. Early identification of fast Earth-directed CME can help provide storm warnings, but detection of such by coronagraphs is extremely difficult. We suggest that energetic hydrogen atoms (EHA) between 2 and 10 keV produced during the transit phase of an Earth-directed CME by recombination between protons and electrons in the CME can travel ahead of the CME and act as harbingers of a magnetic storm. This forecasting scheme should work if enough EHA are produced, because while CMEs decelerate continuously after their ejection, the EHA fluxes produced in the initial phase of fast CMEs propagate at their initial high speeds (> 1 X 103 km s-1). Model simulations support this proposed mechanism. A coarse measurement of the CME-produced ENA at 1 AU could provide storm warning hours in advance, and finer measurements could yield detailed information on the likely geomagnetic effectiveness of a CME, as well as the evolution and propagation of CME between the Sun and Earth.

Hsieh, Ke C.; Shih, K.-L.; McComas, David J.; Wu, Shi T.; Wu, C. C.

1992-06-01

40

Global and local optical model parameterizations. [A > 40, 10 keV-20 MeV  

SciTech Connect

A review is given of global and regional phenomenological neutron optical model parameterizations in the mass region above A = 40 and for neutron energies in the range 10 keV to 20 MeV. The performance of some 11 different neutron parameterizations is investigated for the case of /sup 58/Ni, utilizing Hauser-Feshbach statistical theory calculations of several reactions. A similar, more restricted analysis is made for neutron reactions on /sup 165/Ho, demonstrating the use of two useful approximations in deformed optical model calculations. A regional actinide potential is adapted for use with /sup 165/Ho and is shown to give reasonable results for /sup 165/Ho, /sup 238/U, and /sup 242/Pu. 32 refs., 8 figs., 2 tabs.

Young, P.G.

1985-01-01

41

CCD imaging from 20 eV to 8 keV  

Microsoft Academic Search

Pulsed x-ray diagnostics operating in the kilovolt and sub-kilovolt regimes are required in the study of x-ray laser schemes. Sensitivity and dynamic range measurements are presented for position-sensitive detector systems, designed and optimized for these spectral regions. Both systems employ cooled, multi-pinned phase CCD's for image capture. For photon energies from 20 eV to 1 keV (where direct detection with

A. G. Macphee; C. L. S. Lewis

1995-01-01

42

CCD imaging from 20 eV to 8 keV  

Microsoft Academic Search

Pulsed x-ray diagnostics operating in the kilovolt and sub-kilovolt regimes are required in the study of x-ray laser schemes. Sensitivity and dynamic range measurements are presented for position-sensitive detector systems, designed and optimized for these spectral regions. Both systems employ cooled, multi-pinned phase CCDs for image capture. For photon energies from 20 eV to 1 keV (where direct detection with

A. G. MacPhee; C. L. S. Lewis

1995-01-01

43

A STRONG EXCESS IN THE 20-100 keV EMISSION OF NGC 1365  

SciTech Connect

We present a new Suzaku observation of the obscured active galactic nucleus in NGC 1365, revealing an unexpected excess of X-rays above 20 keV of at least a factor approx2 with respect to the extrapolation of the best-fitting 3-10 keV model. Additional Swift-BAT and Integral-IBIS observations show that the 20-100 keV is concentrated within approx1.5 arcmin from the center of the galaxy, and is not significantly variable on timescales from days to years. A comparison of this component with the 3-10 keV emission, which is characterized by a rapidly variable absorption, suggests a complex structure of the circumnuclear medium, consisting of at least two distinct components with rather different physical properties, one of which covers >80% of the source with a column density N {sub H} approx 3-4x10{sup 24} cm{sup -2}. An alternative explanation is the presence of a double active nucleus in the center of NGC 1365.

Risaliti, G.; Elvis, M.; Fabbiano, G.; Wang, J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St. Cambridge, MA 02138 (United States); Braito, V. [Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Laparola, V. [INAF-IASF, Via U. La Malfa 153, 90146 Palermo (Italy); Bianchi, S.; Matt, G. [Dipartimento di fisica, Universita degli Studi 'Roma Tre', Via della Vasca Navale 84, I-00146 Roma (Italy); Maiolino, R. [INAF-Osservatorio Astronomico di Roma via di Frascati, 33 00040 Monte Porzio Catone, Roma (Italy); Reeves, J. [Astrophysics Group, School of Physical and Geographical Science, Keele University, Keele, Staffordshire ST5 5BG (United Kingdom); Salvati, M., E-mail: grisaliti@cfa.harvard.ed [INAF-Osservatorio di Arcetri, Largo E. Fermi 5, I-50125, Firenze (Italy)

2009-11-01

44

183W Resonance Parameter Evaluation in the Neutron Energy Range Up to 5 keV  

SciTech Connect

We generated a preliminary set of resonance parameters for {sup 183}W in the neutron energy range of thermal up to 5 keV. In the analyzed energy range, this work represents a significant improvement over the current resonance evaluation in the ENDF/B-VII.1 library limited up to 2.2 keV. The evaluation methodology uses the Reich-Moore approximation to fit, with the R-matrix code SAMMY, the high-resolution measurements performed in 2007 at the GEel LINear Accelerator (GELINA) facility. The transmission data and the capture cross sections calculated with the set of resonance parameters are compared with the experimental values, and the average properties of the resonance parameters are discussed.

Pigni, Marco T [ORNL; Dunn, Michael E [ORNL; Guber, Klaus H [ORNL

2012-01-01

45

Multiple scattering of 5-30 keV electrons in evaporated metal films II: Range-energy relations  

Microsoft Academic Search

The ranges of electrons in evaporated films of aluminium, copper, silver and gold have been measured for incident energies E0 between 5 and 20 keV. From electron transmission measurements the maximum range and the extrapolated range were determined. Energy loss measurements gave the mean range and the Thomson-Whiddington range, corresponding to the mean energy Em and the most probable energy

V. E. Cosslett; R. N. Thomas

1964-01-01

46

Measurement of the {sup 237}Np(n,{gamma}) cross section from 20 meV to 500 keV with a high efficiency, highly segmented 4{pi} BaF{sub 2} detector  

SciTech Connect

The {sup 237}Np(n,{gamma}){sup 238}Np cross section has been measured in the neutron energy range from 20 meV to 500 keV using the DANCE array at the Los Alamos National Laboratory. This new facility allows experiments with submilligram samples and is therefore well suited to investigate isotopes with half-lives as low as a few hundred days. In this benchmark measurement, only 0.42 mg of {sup 237}Np was sufficient to determine differential cross sections relative to the well-known resonance at 0.5 eV. The thermal cross section was measured to {sigma}{sub 2200m/s}=177{+-}5 barn, {sigma}{sub kT=25.3meV}=167{+-}4 barn and the resonance integral to RI=693{+-}6 barn.

Esch, E.-I.; Bond, E. M.; Bredeweg, T. A.; Couture, A.; Glover, S. E.; Haight, R. C.; Jandel, M.; Kawano, T.; Mertz, A.; O'Donnell, J. M.; Rundberg, R. S.; Schwantes, J. M.; Ullmann, J. L.; Vieira, D. J.; Wilhelmy, J. B.; Wouters, J. M. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Reifarth, R. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Colorado School of Mines, Golden, Colorado 80401 (United States); Greife, U.; Hatarik, A. M.; Hatarik, R. [Colorado School of Mines, Golden, Colorado 80401 (United States)

2008-03-15

47

Determination of the details of the resonance structure of both the total cross section and the fission cross section of /sup 235/U and /sup 239/Pu for 2 ev-20-Kev neutrons  

SciTech Connect

When fast reactors are calculated with the aid of the system of BNAB group constants, one must know both the average group cross sections of the fuel nuclides and the design materials and the factors of their resonance self-shielding. It is necessary to directly measure the average characteristics of the resonance structures of the cross sections at resolved and unresolved resonances. The present work presents the results of measurements of those characteristics; the measurements were made with the technique of neutron transmission and self-indication in /sup 235/U and /sup 239/Pu: the average total cross sections and the factors of the resonance self-shielding of the total cross section and the fission cross section were determined at 2 ev-20 keV. 10 refs.

Van'kov, A.A.; Grigor'ev, Yu.V.; Ukraintsev, V.F.; Bakalov, T.; Ilchev, G.; Toshkov, S.; Chan-Khan'-Mai; Yaneva, N.

1980-06-01

48

Calibration of SIOM-5FW film in the range of 0.1-4 keV  

NASA Astrophysics Data System (ADS)

The SIOM-5FW film produced for the sub-keV x-ray detection range was calibrated here in a wide energy range (0.1-4 keV). A single set of parameters valid in the whole measured energy range was determined for the calibration of the Shangai 5F (SIOM-5FW) film from a parametric fit of the data. The sensitivity of the SIOM-5FW film was measured to be four times lower than that of the Kodak DEF film at 2.5 keV photon energy. Modeling of the DEF and SIOM-5FW films provides a good comparison of their sensitivity in the 0.1-10 keV range.

Chenais-Popovics, C.; Reverdin, C.; Ioannou, I.

2006-06-01

49

Calibration of semiconductor detectors in the 200-8500 keV range at VNIIM.  

PubMed

At the ionising radiation department of the D.I. Mendeleyev Institute for Metrology, a semiconductor detector was calibrated in the energy range 200-8500 keV using (n,2?) and (n,?) reactions. Separate cylindrical targets (77 mm diameter and 10mm height) were made from mercuric sulphate, sodium chloride and metallic titanium. A (252)Cf spontaneous fission neutron source, placed in 150 mm diameter polyethylene ball, was used to generate thermal neutrons. The optimal target dimensions were determined taking into account the thermal neutron cross-sections and gamma-radiation attenuations in the target materials. The influence of the background radiation induced by neutrons from the walls, floors and ceilings was also taken into account. The shapes of the efficiency curves for point and volume sources in the 200-8500 keV range have been investigated. The experimental results are in good agreement with Monte-Carlo calculations. The emission rate of the 6.13 MeV photons from a (238)Pu-(13)C source was determined with an expanded uncertainty, U(c), of 10% (k=2). PMID:22512978

Tereshchenko, Evgeny E; Moiseev, Nikolay

2012-04-04

50

The Spectrum of GRB 930131 (``Superbowl Burst'') from 20 KEV to 200 MEV  

NASA Astrophysics Data System (ADS)

We have constructed a broadband spectrum for GRB 930131 (the ``Superbowl Burst''), ranging from 20 keV to 200 MeV, by combining spectral information from the Gamma Ray Observatory's BATSE, COMPTEL, and EGRET instruments. We present general methods for combining spectra from different time intervals obtained by the same instrument as well as for combining spectra from the same time interval taken by different instruments. The resulting spectrum is remarkably flat (in nuF_nu-space) up to high energies. We find that the spectral shape can be successfully fitted by the shocked synchrotron emission model of Tavani. We present evidence that the flatness of the spectrum at high energies is not due to spectral time variability.

Bromm, Volker; Schaefer, Bradley E.

1999-08-01

51

Optical emission from metal targets bombarded by 5-20 keV argon ions  

NASA Astrophysics Data System (ADS)

The spectral composition of optical emission from high-purity iron (99.99% Fe), zirconium (99.98% Zr), and tungsten (99.96% W) targets bombarded by 5-20 keV Ar+ ions has been studied. The ion-bombardment-induced emission spectra of all metals exhibit two broad bands in the visible and IR spectral range. The first band is assigned to the emission from thermal spikes representing nanosized regions heated to 5000-6000 K, which are formed at the target surface in the course of evolution of high-density atomic collision cascades. The presence of an IR emission band is explained by the integral heating of targets to 500-800 K in the course of ion irradiation. This interpretation is confirmed by agreement between the experimentally measured and calculated temperatures in the region of thermalized collision cascades and the relative intensities of emission bands.

Ovchinnikov, V. V.; Makhin'ko, F. F.; Solomonov, V. I.; Gushchina, N. V.; Kaigorodova, O. A.

2012-01-01

52

X-Ray Detector Calibrations in the 280-Ev to 100-Kev Energy Range.  

National Technical Information Service (NTIS)

The absolute sensitivity for several different types of radiation detectors has been measured using x-rays in the energy range of 280 eV to 100 keV. The photons in this energy range are produced using three separate x-ray-generating facilities. The detect...

J. L. Gaines R. W. Kuckuck R. D. Ernst

1976-01-01

53

The 3H(?, ?)7Li reaction in the energy range from 0.7 to 2.0 Mev  

NASA Astrophysics Data System (ADS)

Differential cross sections for the 3H(?, ?)7Li (g.s.) and the 3H(?, ?)7Li (0.478 MeV) reactions have been measured at 0 in the alpha-particle energy range from 0.7 to 2.0 MeV. A Ge(Li) detector has been used to measure the gamma rays. The results have been compared with recent theoretical calculations of Mertelmeier and Hoffman employing the resonanting group method and a good agreement has been found.

Burzy?ski, S.; Czerski, K.; Marcinkowski, A.; Zupranski, P.

1987-10-01

54

Characterization of zone plate properties using monochromatic synchrotron radiation in the 2 to 20 nm wavelength range.  

PubMed

A zone plate composed of Mo zones having 4 mm outermost zone diameter, 100 nm outermost zone width, and supported on a silicon nitride membrane was characterized using monochromatic synchrotron radiation in the 2 to 20 nm wavelength range. The zero and first order efficiencies were measured and compared to ab initio calculations that account for the optical properties of the materials, the width and shape of the zones, and multiple-layer thin-film effects. It is shown that the thicknesses of the Mo zones and the membrane and the ratio of the zone width to zone period can be independently determined from the measured diffraction efficiencies in the zero and first orders and that the computational code can be used to reliably design zone plates that are optimized for applications such as solar irradiance monitors in the extreme ultraviolet region. PMID:21691369

Seely, John; Kjornrattanawanich, Benjawan; Goray, Leonid; Feng, Yan; Bremer, James

2011-06-20

55

Characterization of Zone Plate Properties using Monochromatic Synchrotron Radiation in the 2 to 20 nm Wavelength Range  

SciTech Connect

A zone plate composed of Mo zones having 4 mm outermost zone diameter, 100 nm outermost zone width, and supported on a silicon nitride membrane was characterized using monochromatic synchrotron radiation in the 2 to 20 nm wavelength range. The zero and first order efficiencies were measured and compared to ab initio calculations that account for the optical properties of the materials, the width and shape of the zones, and multiple-layer thin-film effects. It is shown that the thicknesses of the Mo zones and the membrane and the ratio of the zone width to zone period can be independently determined from the measured diffraction efficiencies in the zero and first orders and that the computational code can be used to reliably design zone plates that are optimized for applications such as solar irradiance monitors in the extreme ultraviolet region.

J Seely; B Kjornrattanawanich; L Goray; Y Feng; J Bremer

2011-12-31

56

Characterization of zone plate properties using monochromatic synchrotron radiation in the 2 to 20 nm wavelength range  

SciTech Connect

A zone plate composed of Mo zones having 4 mm outermost zone diameter, 100 nm outermost zone width, and supported on a silicon nitride membrane was characterized using monochromatic synchrotron radiation in the 2 to 20 nm wavelength range. The zero and first order efficiencies were measured and compared to ab initio calculations that account for the optical properties of the materials, the width and shape of the zones, and multiple-layer thin-film effects. It is shown that the thicknesses of the Mo zones and the membrane and the ratio of the zone width to zone period can be independently determined from the measured diffraction efficiencies in the zero and first orders and that the computational code can be used to reliably design zone plates that are optimized for applications such as solar irradiance monitors in the extreme ultraviolet region.

Seely, John; Kjornrattanawanich, Benjawan; Goray, Leonid; Feng Yan; Bremer, James

2011-06-20

57

Ranges and stopping power of KeV electrons in the solid hydrogens  

Microsoft Academic Search

1-3 keV electron ranges and stopping power in the solid hydrogens have been investigated by the Monte Carlo simulation method on the basis of experimental thin film measurements. In the simulation, elastic scattering cross sections are calculated exactly using the single-atom crystalline potentials. Inelastic processes for gold are treated by modifying Gryzinski's semiempirical expression for each core and valence electron

S. Valkealahti; J. Schou; H. Srensen; R. M. Nieminen

1988-01-01

58

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

Microsoft Academic Search

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 130?m shows a potential to be used as an effective X-ray absorber below 20keV.

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

2006-01-01

59

Luminescent collisions of He+ and He++ ions with H2 molecules at energies below 2 keV  

NASA Astrophysics Data System (ADS)

Spectroscopic studies of collisions between He+ and He++ ions with H2 gas target have been performed in the 200-600 nm wavelength range. Atomic lines of hydrogen Balmer series and several helium lines were identified and their excitation functions between 50 eV and 1 keV (2 keV for He++) were determined.

Pranszke, B.; Werbowy, S.; Miotk, R.; Borkowski, K. J.; Kowalski, A.

2013-10-01

60

Scattering of noble gas clusters with energies in the keV range  

SciTech Connect

Noble gas clusters with an average size of several thousand atoms and with energies in the keV range were directed at metal surfaces under small angles of incidence. The scatter products were examined with respect to size, energy, and recoil angle. All observations fit an impact model in which the tangential momentum is preserved during impact, while the normal kinetic energy is converted to cluster heat. The associated temperature rise results in the evaporation of cluster atoms. Small clusters evaporate completely; large clusters are reduced in size. The evaporated atoms continue in a forward direction (together with the residual cluster fragments) and form a well-collimated and energetic atom beam.

Knauer, W. (Hughes Research Laboratories, 3011 Malibu Canyon Road, Malibu, California 90265 (US))

1990-01-01

61

Parametrization of the total photon mass attenuation coefficients in the energy range 0.1-1000 keV  

NASA Astrophysics Data System (ADS)

It is convenient to generate mass attenuation coefficients using semi-empirical schemes. The validity of most of the existing schemes is limited to a relatively narrow energy interval (1-40 keV) and their accuracies are poor in some energy regions. In this work, a semi-empirical scheme flexible enough to give a good fit to data in a very wide photon energy range (0.1-1000 keV) was employed. Fitting coefficients for the entire range were obtained by utilizing mass attenuation data from two sources: (1) semi-empirical data of Henke et al. in the low photon energy region, and (2) theoretical values generated with the XCOM code for fitting in the high energy region. The root mean square of the fit is generally less than 0.2% except for energies below 1 keV where the available data are scattered. A computer code for generating mass attenuation coefficients based on the proposed scheme has been developed.

Orlic, I.; Loh, K. K.; Sow, C. H.; Tang, S. M.; Thong, P.

1993-05-01

62

Electron scattering by N 2 and CO at intermediate energies: 110 keV  

Microsoft Academic Search

Semi-empirical total cross sections for electron scattering from N2 and CO in the energy range 110 keV have been obtained by combining transmission-beam measurements for impact energies up to 5 keV with an asymptotic behaviour at high energy according to the Born-Bethe approximation. The influence of the forward electron scattering in our experimental systems has been evaluated by means of

G. Garca; M. Roteta; F. Manero

1997-01-01

63

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

SciTech Connect

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.

Wang, C.L.; Leipelt, G.R.; Nilson, D.G.

1984-10-03

64

Energetic (keV) Ionosphere-Origin Ions Found Between R= 2 and 23 R E  

NASA Astrophysics Data System (ADS)

With the flight of ion composition instruments on the Polar satellite, beginning some eight years ago, adding to several earlier missions of varied orbits, we now have essentially contiguous altitude records of the outflow of energized ionospheric ions from R= 2 R E (geocentric) to R= 23 R E, at least in the energy range from a few tens of eV/e to a few tens of keV/e. Magnetotail ion composition measurements in that energy range were first made more than 20 years ago during the ISEE mission (within 23 R E) and are again being made with the Cluster satellites (within 20 R E). According to the several years of ISEE measurements, the nearly omnipresent, singly charged oxygen ions, in particular, have a broad energy distribution within the tail plasma sheet, typically averaging about 3-5 keV. This may be contrasted with mean O+ energies of only 0.2-0.4 keV observed in the ion outflow at R 2 R E by the Polar TIMAS instrument. The same instrument finds the O+ mean energy to have increased to 1 keV or more by the time the ions have reached R 4-9 R E, while the total rate of O+ outflow (ions per second) above the nominal 15 eV minimum energy (plus spacecraft potential) has increased about fivefold. An important part of this progressive energization is transverse acceleration across the geomagnetic field lines. As will be shown, this process is sometimes resolved within the O+ gyro period by the TIMAS instrument at these high altitudes. Early TIMAS results suggest that this kind of acceleration is intermittent and explosive and arguably caused by magnetic field-aligned space charge structures associated with earthward bursts of hot and filamentary magnetospheric plasma. The TIMAS data also imply that ionospheric ions are directly injected into the ring current region, but the very energetic O+ (~100 keV) that is known to be a large component of the storm-time ring current has most likely arrived from the plasma sheet, undergoing adiabatic betatron and Fermi acceleration.

Lennartsson, O. W.

2004-05-01

65

Monochromator harmonic content measurements and calculations at energies above 20 keV  

SciTech Connect

Measurements of the harmonic content from single and double crystal silicon monochromators have been made in the 20 to 100 keV at the X17 Superconducting Wiggler Beamline at the NSLS. These measurements are compared with calculations which estimate the monochromatic beam harmonic content and the detection system efficiency with good agreement. At high photon energies ( > 20keV), the scattering of x-rays from an amorphous scatterer is dominated by the inelastic Compton process. At large scattering angles this will completely overwhelm the more forward directed elastic scattering. The Compton x-ray energy shift is large enough to make the distinction between elastic and Compton scattering unambiguous when a spectrum is acquired with a solid state detector. This shift, which is energy dependent, allows the measurement of the relative harmonic intensity in a way that is not affected by pulse pileup in the detector and electronics. The present measurements were done to assess the level of harmonic contamination from two monochromator systems both used on the X17 beamline: the single crystal type monochromator for the Digital Subtraction Coronary Angiography project; and the double crystal monochromator being developed for the Multiple Energy Computed Tomography (MECT) project and the Materials Science program. 5 refs.

Chapman, D.; Moulin, H.; Garrett, R.F.

1991-01-01

66

A low background-rate detector for ions in the 5 to 50 keV energy range to be used for radioisotope dating with a small cyclotron  

SciTech Connect

Accelerator mass spectrometry in tandem Van de Graaff accelerators has proven successful for radioisotope dating small samples. We are developing a 20 cm diameter 30 to 40 keV cyclotron dedicated to high-sensitivity radioisotope dating, initially for /sup 14/C. At this energy, range and dE/dx methods of particle identification are impossible. Thus arises the difficult problem of reliably detecting 30 to 40 keV /sup 14/C at 10/sup -2/ counts/sec in the high background environment of the cyclotron, where lower energy ions, electrons, and photons bombard the detector at much higher rates. We have developed and tested an inexpensive, generally useful ion detector that allows dark-count rates below 10/sup -4/ counts/sec and excellent background suppression. With the cyclotron tuned near the /sup 13/CH background peak, to the frequency for /sup 14/C, the detector suppresses the background to 6 x 10/sup -4/ counts/sec. For each /sup 14/C ion the detectors grazing-incidence Al/sub 2/O/sub 3/ conversion dynode emits about 20 secondary electrons, which are independently multiplied in separate pores of a microchannel plate. The output signal is proportional to the number of secondary electrons, allowing pulse-height discrimination of background. We have successfully tested the detector with positive /sup 12/C, /sup 23/Na, /sup 39/K, /sup 41/K, /sup 85/Rb, /sup 87/Rb, and /sup 133/Cs at 5 to 40 keV, and with 36 keV negative /sup 12/C and /sup 13/CH. It should detect ions and neutrals of all species, at energies above 5 keV, with good efficiency and excellent background discrimination. Counting efficiency and background discrimination improve with higher ion energy. The detector can be operated at least up to 2 x 10/sup -7/ Torr and be repeatedly exposed to air. The maximum rate is 10/sup 6.4/ ions/sec in pulse counting mode and 10/sup 9.7/ ions/sec in current integrating mode.

Friedman, P.G.

1986-11-25

67

2-gamma decay of the 662-keV isomer in ^137Ba  

NASA Astrophysics Data System (ADS)

2-gamma decay of the 662-keV ^137Ba isomer following ^137Cs beta decay has been observed using two 3"x3" NaI detectors, a 20.5-?Ci source, and a Pb shielding geometry designed to minimize direct and sequential Compton scattering backgrounds. In runs totaling 144 days, a 662-keV peak has been observed in the profile across the diagonal connecting 662-keV axis points in a 2-dimensional coincidence pulse-height spectrum. A preliminary value of 2.0(6)x10-6 is derived for the 2-gamma/1-gamma intensity ratio. The distribution of 662-keV events along the 2D diagonal is a continuum centered at 331-331 keV with a shape favoring a double quadrupole E2-M2 or M2-E2 decay sequence. Our result compares with upper limits of < 10-5, our assessment of the Beusch experiment [1], and < 2.2x10-6 by Basenko et al. [2]. It will be compared with theoretical estimates. [4pt] [1] W. Beusch, Helv Phys. Acta 33, 363 (1960)[0pt] [2] V.K. Basenko, A.N. Berlizov, and G.A. Prokopets, Bull. Russ. Acad. Sci. 56, 94 (1992)

Millener, D. J.; Sutter, R. J.; Alburger, D. E.

2011-10-01

68

Cluster dynamics in the range N=2-20: High resolution infrared spectra of HeN-CO  

NASA Astrophysics Data System (ADS)

Infrared spectra of HeN-CO complexes with N up to about 20 have been observed in the 2145 cm-1 region of the C-O stretch vibration using a tunable diode laser spectrometer to probe pulsed supersonic expansions from moderately high pressure (<=40 atm) cooled (>-150 C) jet sources. Cooler (<=0.2 K) or warmer (<=0.5 K) effective rotational temperatures were obtained using pinhole or slit jet nozzles, respectively. Two series of R(0) transitions were observed, each correlating smoothly with the known a-type (K=0<--0) and b-type (K=1<--0) R(0) lines of the binary complex, He-CO. Although the b-type series starts off about 7 times stronger for N=1, it was observed to lose intensity to the a series with increasing N-value. The numbering of cluster size was reliably established up to N=14 for the a-type and N=6 for the b-type series. Some warmer lines due to higher J-value transitions [e.g., R(1)] were observed and tentatively assigned, but these were not sufficient to enable rotational analysis. Thus it has not yet been possible to separate the effects of vibrational shifts and rotational dynamics on the line positions. Two critical regions were observed in the cluster size evolution around N=7 and 15, and these may be related to the theoretically calculated maximum and minimum, respectively, in the incremental binding energy per helium atom.

Tang, Jian; McKellar, A. R. W.

2003-07-01

69

20-150-keV proton-impact-induced ionization of uracil: Fragmentation ratios and branching ratios for electron capture and direct ionization  

SciTech Connect

Fragmentation ratios and branching ratios are measured for ionization and dissociative ionization for 20-150 keV (0.9-2.4v{sub 0}) proton collisions with gas-phase uracil molecules. Through event-by-event determination of the postcollision projectile charge, it is possible for such a key biomolecule to distinguish between electron capture (EC) by the incident proton and direct ionization (DI) without projectile neutralization. While the same fragment ion groups are observed in the mass spectra for both processes, EC induces dissociation with greater efficiency than DI in the impact energy range of 35-150 keV (1.2-2.4v{sub 0}). In this range EC is also less abundant than DI with a branching ratio for EC/total ionization of <50%. Moreover, whereas fragmentation ratios do not change with energy in the case of EC, DI mass spectra show a tendency for increased fragmentation at lower impact energies.

Tabet, J.; Eden, S.; Feil, S.; Abdoul-Carime, H.; Farizon, B.; Farizon, M.; Ouaskit, S.; Maerk, T. D. [Universite de Lyon, F-69003, Lyon (France); Universite Lyon 1, Villeurbanne, CNRS/IN2P3, UMR5822, Institut de Physique Nucleaire de Lyon, F-69622 Villeurbanne (France)

2010-01-15

70

Ranges and depth distributions of 200-keV He ions channeled in Si, Ge, and GaAs crystals  

SciTech Connect

We report depth distributions of 200-keV He ions channeled in the <100> and <110> directions of Si, Ge, and GaAs crystals and in a random orientation of each crystal, measured using secondary ion mass spectrometry. The <100> channeled profiles agree with the random profiles within experimental error. The <110> channeled profiles are about 1.7, 2.3, and 2.2 times as deep as the random peaks (projected range) for the three crystals, respectively. Assuming velocity-proportional electronic stopping, values of electronic stopping are calculated for He in Si, Ge, and GaAs. Fractions of He ions backscattered into the vacuum are estimated. Profiles for Ge and GaAs, with the same average atomic number, are compared. Range and profile shape parameters are tabulated.

Wilson, R.G.

1987-04-01

71

Stopping powers and extrapolated ranges for electrons (1-10 keV) in metals  

Microsoft Academic Search

A thin film quasiadiabatic calorimeter has been applied to the measurement of the stopping power for electrons, under conditions of small angle scattering, in Al, Ni, Cu, Ag and Au in the energy region 1 keV to 10 keV. Results are presented with an estimated precision of 15%. Corrections are included for the multiple scattering enhancement of the apparent path

K O Al-Ahmad; D E Watt

1983-01-01

72

100 keV electron backscattered range and coefficient for silicon.  

SciTech Connect

The authors have measured the range and intensity of backscattered electrons in silicon from a 100 keV source using a process independent method. Backscattered electrons contributed to the total dose of features written in a negative tone electron beam resist. Instead of measuring the height of the resist and using a contrast curve to convert the resist height to dose, the heights of the features were made equal by adjusting the backscattered contribution through dose assignments. Creating features of equal height eliminated the need to use a contrast curve to convert from resist height to total dose. Also, it allowed for measurements of the backscattered contribution from larger distances. Using a circularly symmetric torus pattern, the three-dimensional backscatter problem was reduced to a 1-dimensional Gaussian form. The authors measured the range of the backscattered electrons, {beta}, to be 31.08 {+-} 0.06 {micro}m. By varying the writing dose of the pattern, we determined the backscatter coefficient, {eta}, to be 0.63 {+-} 0.03.

Czaplewski, D.A.; Ocola, L.E. (Center for Nanoscale Materials)

2012-01-01

73

Production and performance of the inFOCmicroS 20-40-keV graded multilayer mirror.  

PubMed

The International Focusing Optics Collaboration for microCrab Sensitivity (InFOCmicroS) balloonborne hard x-ray telescope incorporates graded Pt/C multilayers replicated onto segmented Al foils to obtain the significant effective area at energies previously inaccessible to x-ray optics. Reflectivity measurements of individual foils demonstrate our capability to produce a mass quantity of multilayered foils with a rms roughness of 0.5 nm. The effective area of the completed mirror is 78 and 22 cm2 at 20 and 40 keV, respectively. The measured half-power diameter is 2.0 +/- 0.6 are min (90% confidence). The successful completion of this mirror demonstrates its applicability to future x-ray telescopes such as Constellation-X. PMID:12683767

Berendse, Fred; Owens, Scott M; Serlemitsos, Peter J; Tueller, Jack; Chan, Kai-Wing; Soong, Yang; Krimm, Hans; Baumgartner, Wayne H; Ogasaka, Yasushi; Tamura, Keisuke; Okajima, Takashi; Tawara, Yuzuru; Yamashita, Koujun; Misaki, Kazutami; Kunieda, Hideyo

2003-04-01

74

5 keV to 2 MeV lithium implantation and diffusion in amorphous silicon  

Microsoft Academic Search

Low dose implanted lithium depth profiles in preamorphized silicon have been measured in the energy range of 5 keV to 2 MeV by means of three different nuclear reaction techniques and SIMS measurements, and they are compared to theory. Though the agreement is good for the mean projected range, we find systematic deviations for the range straggling.Further, the shapes of

D. Fink; J. P. Biersack; H. P. Schoelch; M. Weiser; S. Kalbitzer; M. Behar; J. P. De Souza; F. C. Zawislak; A. M. Mazzone; H. Kranz

1989-01-01

75

High Resolution, 20-100 keV X-ray Backlighters for ICF and HEDS Experiments  

NASA Astrophysics Data System (ADS)

We are studying the feasibility of high resolution radiography using short pulse high intensity lasers. Specifically we wish to better characterize and optimize the Kalpha X-ray production and brightness created by relativistic electron plasma interactions in the target material. We plan to utilize this Kalpha source as a backlighter to image various stages of implosions and planar driven high Z materials. Particularly interesting are the production of Kalpha's in the range 20 100 keV. In order to assess in detail the characteristics of such high energy X-ray backlighters, we are performing experiments using the 10 J, 100 fs JanUSP laser at LLNL. We will measure Kalpha source generation efficiency as function of laser beam parameters such as pulse duration, spot size and laser beam energy. We are also developing a high resolution hard X-ray imaging detector system. This paper will present initial results from the JanUSP experiments. Reference:D.K. Bradley, O.L. Landen, A.B. Bullock, S.G. Glendinning, and R.E. Turner, "Efficient, High Spatial-Temporal Resolution, 1-100 keV X-ray Radiography," Opt. Lett. 27(2002) 134.

Park, Hye-Sook; Koch, J. A.; Landen, O. L.; Phillips, T. W.; Schmid, G. J.

2002-11-01

76

Calculation of electron-impact rotationally elastic total cross sections for NH{sub 3}, H{sub 2}S, and PH{sub 3} over the energy range from 0.01 eV to 2 keV  

SciTech Connect

This paper report results of calculation of the total cross section Q{sub T} for electron impact on NH{sub 3}, H{sub 2}S, and PH{sub 3} over a wide range of incident energies from 0.01 eV to 2 keV. Total cross sections Q{sub T} (elastic plus electronic excitation) for incident energies below the ionization threshold of the target were calculated using the UK molecular R-matrix code through the Quantemol-N software package and cross sections at higher energies were derived using the spherical complex optical potential formalism. The two methods are found to give self-consistent values where they overlap. The present results are, in general, found to be in good agreement with previous experimental and theoretical results.

Limbachiya, Chetan [P. S. Science College, Kadi 382 715, Gujarat (India); Vinodkumar, Minaxi [V. P. and R. P. T. P. Science College, Vallabh Vidyanagar 388 120, Gujarat (India); Mason, Nigel [Department of Physics and Astronomy, Open University, Milton Keynes, MK7 6AA (United Kingdom)

2011-04-15

77

Channeled and random proton stopping power in the 30-1000 keV energy range  

Microsoft Academic Search

The stopping power of 30- to 1000-keV protons transmitted through silicon in random and channeling (, , and ) directions has been determined. It was found that the stopping power for random and all channeling directions reaches a maximum at about 50 keV. At nearly the same energy the ratio of the channeled-to-random stopping has the maximum value. Present results

A. Carnera; G. Della Mea; A. V. Drigo; S. Lo Russo; P. Mazzoldi; G. G. Bentini

1978-01-01

78

A Database of >20 keV Electron Green's Functions of Interplanetary Transport at 1 AU  

NASA Astrophysics Data System (ADS)

We use interplanetary transport simulations to compute a database of electron Green's functions, i.e., differential intensities resulting at the spacecraft position from an impulsive injection of energetic (>20 keV) electrons close to the Sun, for a large number of values of two standard interplanetary transport parameters: the scattering mean free path and the solar wind speed. The nominal energy channels of the ACE, STEREO, and Wind spacecraft have been used in the interplanetary transport simulations to conceive a unique tool for the study of near-relativistic electron events observed at 1 AU. In this paper, we quantify the characteristic times of the Green's functions (onset and peak time, rise and decay phase duration) as a function of the interplanetary transport conditions. We use the database to calculate the FWHM of the pitch-angle distributions at different times of the event and under different scattering conditions. This allows us to provide a first quantitative result that can be compared with observations, and to assess the validity of the frequently used term beam-like pitch-angle distribution.

Agueda, N.; Vainio, R.; Sanahuja, B.

2012-10-01

79

A DATABASE OF >20 keV ELECTRON GREEN'S FUNCTIONS OF INTERPLANETARY TRANSPORT AT 1 AU  

SciTech Connect

We use interplanetary transport simulations to compute a database of electron Green's functions, i.e., differential intensities resulting at the spacecraft position from an impulsive injection of energetic (>20 keV) electrons close to the Sun, for a large number of values of two standard interplanetary transport parameters: the scattering mean free path and the solar wind speed. The nominal energy channels of the ACE, STEREO, and Wind spacecraft have been used in the interplanetary transport simulations to conceive a unique tool for the study of near-relativistic electron events observed at 1 AU. In this paper, we quantify the characteristic times of the Green's functions (onset and peak time, rise and decay phase duration) as a function of the interplanetary transport conditions. We use the database to calculate the FWHM of the pitch-angle distributions at different times of the event and under different scattering conditions. This allows us to provide a first quantitative result that can be compared with observations, and to assess the validity of the frequently used term beam-like pitch-angle distribution.

Agueda, N.; Sanahuja, B. [Departament d'Astronomia i Meteorologia, Institut de Ciencies del Cosmos, Universitat de Barcelona, Barcelona (Spain); Vainio, R. [Department of Physics, University of Helsinki, Helsinki (Finland)

2012-10-15

80

Inelastic processes in K+-He collisions in energy range 0.710 keV  

NASA Astrophysics Data System (ADS)

Absolute cross sections for charge exchange, ionization, stripping, and excitation in K+-He collisions were measured in the ion energy range 0.710 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 ?=60.1 nm and ?=61.2 nm lines is 5:1, which indicates the high probability for excitation of the singlet resonance level 1P1 compared to the triplet level 3P1. 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.

Lomsadze, R. A.; Gochitashvili, M. R.; Kezerashvili, R. Ya.; Mosulishvili, N. O.; Phaneuf, R.

2013-04-01

81

Comparison between an event-by-event Monte Carlo code, NOREC, and ETRAN for electron scaled point kernels between 20 keV and 1 MeV.  

PubMed

An event-by-event Monte Carlo code called NOREC, a substantially improved version of the Oak Ridge electron transport code (OREC), was released in 2003, after a number of modifications to OREC. In spite of some earlier work, the characteristics of the code have not been clearly shown so far, especially for a wide range of electron energies. Therefore, NOREC was used in this study to generate one of the popular dosimetric quantities, the scaled point kernel, for a number of electron energies between 0.02 and 1.0 MeV. Calculated kernels were compared with the most well-known published kernels based on a condensed history Monte Carlo code, ETRAN, to show not only general agreement between the codes for the electron energy range considered but also possible differences between an event-by-event code and a condensed history code. There was general agreement between the kernels within about 5% up to 0.7 r/r (0) for 100 keV and 1 MeV electrons. Note that r/r (0) denotes the scaled distance, where r is the radial distance from the source to the dose point and r (0) is the continuous slowing down approximation (CSDA) range of a mono-energetic electron. For the same range of scaled distances, the discrepancies for 20 and 500 keV electrons were up to 6 and 12%, respectively. Especially, there was more pronounced disagreement for 500 keV electrons than for 20 keV electrons. The degree of disagreement for 500 keV electrons decreased when NOREC results were compared with published EGS4/PRESTA results, producing similar agreement to other electron energies. PMID:17219152

Cho, Sang Hyun; Vassiliev, Oleg N; Horton, John L

2007-01-12

82

Neutron Capture and Fission Cross Section of Americium-243 in the Energy Range from 5 to 250 KeV.  

National Technical Information Service (NTIS)

The neutron capture and subthreshold fission cross section of exp 243 Am was measured in the energy range from 5 to 250 keV using exp 197 Au and exp 235 U as the respective standards. Neutrons were produced via the exp 7 Li(p,n) and the T(p,n) reaction wi...

K. Wisshak F. Kaeppeler

1983-01-01

83

High-resolution integrated germanium Compton polarimeter for the {gamma}-ray energy range 80 keV--1 MeV  

SciTech Connect

Parameters which govern the choice of a detection system to measure the linear polarization of {gamma} 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 {gamma} rays from the {sup 168}Er({alpha},2{ital n}){sup 170}Yb reaction at {ital E}{sub {alpha}}=25 MeV. Polarization measurements at energies as low as 84 keV have been achieved, where the sensitivity was 0.32{plus_minus}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} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

Sareen, R.A.; Urban, W.; Barnett, A.R.; Varley, B.J. [Department of Physics and Astronomy, University of Manchester, Manchester M13 9PL (United Kingdom)

1995-06-01

84

K-(alpha) Radiography at 20-100 keV Using Short-Pulse Lasers.  

National Technical Information Service (NTIS)

X-ray radiography is an important tool for diagnosing and imaging planar and convergent hydrodynamics phenomena for laser experiments. Until now, hydrodynamics experiments at Omega and NIF utilize E(sub x-ray) < 9 keV backlighter x-rays emitted by thermal...

H. D. Park D. Chambers R. Clarke R. Eagleton E. Giraldez T. Goldsack

2005-01-01

85

Calibration system for electron detectors in the energy range from 10 eV to 50 keV  

Microsoft Academic Search

A system for calibrating electron detectors operating in the energy range 10 eV-50 keV is described. The main component of the system is a large area (730 sq cm) monoenergetic electron beam which is tunable with respect to energy. The beam is produced by illuminating a thin gold film deposited onto a quartz flat with ultraviolet light such that photoelectrons

F. J. Marshall; D. A. Hardy; A. Huber; J. Pantazis; J. McGarity; E. Holeman; J. D. Winningham

1986-01-01

86

ANGULAR DISTRIBUTIONS OF AURORAL ELECTRONS IN THE ENERGY RANGE 0.8 TO 16 keV  

Microsoft Academic Search

Auroral particle fluxes have been measured by detectors aboard the low-altitude, polar- orbiting satellite OVI 18. Electron pitch-angle distributions in the energy range 0.8 to 16 kev are presented for a 3-month period in 1969. The distributions at all energies were found to be predominantly isotropic for intensities above a few times 106 (cmsec step key) -x, inde- pendent of

G. Paschmann; R. G. Johnson; R. D. Sharp; E. G. Shelley

1972-01-01

87

Theoretical cross sections for keV antiprotons  

NASA Astrophysics Data System (ADS)

Partial and total close-coupled semiclassical (impact parameter) cross sections and total classical Monte-Carlo cross sections for interactions inbar p + Ps andbar p, p+H collisions are computed in the intermediate keV range for antiprotons,bar p, up to 100 keV lab. Total cross sections for antihydrogen,bar H, formation are found to be large, 10-2010-16 cm2 in a wider energy range than was anticipated earlier, up to some 20 keV lab. New estimates of cross sections for ionisation of atomic hydrogen by antiproton impact are reported for the low-energy range 1 30 keV lab where they are 10-2010-17 cm2, being much larger than the corresponding cross sections for ionisation of hydrogen by proton impact. Data for excitation of H bybar p impact is also presented.

Ermolaev, A. M.

1989-03-01

88

Strength of the Ec.m.=1113 keV resonance in 20Ne(p,?)21Na  

NASA Astrophysics Data System (ADS)

The 20Ne(p,?)21Na reaction is the starting point of the NeNa cycle, which is an important process for the production of intermediate mass elements. The Ec.m.=1113 keV resonance plays an important role in the determination of stellar rates for this reaction since it is used to normalize experimental direct capture yields at lower energies. The commonly accepted strength of this resonance, ??=1.130.07 eV, has been misinterpreted as the strength in the center-of-mass frame when it is actually the strength in the laboratory frame. This has motivated a new measurement of the Ec.m.=1113 keV resonance strength in 20Ne(p,?)21Na using the DRAGON recoil mass spectrometer. The DRAGON result, 0.9720.11 eV, is in good agreement with the accepted value when both are calculated in the same frame of reference.

Christian, G.; Hutcheon, D.; Akers, C.; Connolly, D.; Fallis, J.; Ruiz, C.

2013-09-01

89

20-100 keV properties of cataclysmic variables detected in the INTEGRAL\\/IBIS survey  

Microsoft Academic Search

Analysis of INTEGRAL\\/IBIS survey observations has revealed that the rare intermediate polar and asynchronous polar cataclysmic variables (CVs) are consistently found to emit in the 20-100 keV energy band, whereas synchronous polars and the common non-magnetic CVs rarely do so. From the correlation of a candidate INTEGRAL\\/IBIS survey source list with a CV catalogue, 15 CV detections by IBIS have

E. J. Barlow; C. Knigge; A. J. Bird; A. J Dean; D. J. Clark; A. B. Hill; M. Molina; V. Sguera

2006-01-01

90

Full-field microimaging with 8 keV X-rays achieves a spatial resolutions better than 20 nm.  

PubMed

Fresnel zone plates (450 nm thick Au, 25 nm outermost zone width) used as objective lenses in a full field transmission reached a spatial resolution better than 20 nm and 1.5% efficiency with 8 keV photons. Zernike phase contrast was also realized without compromising the resolution. These are very significant achievements in the rapid progress of high-aspect-ratio zone plate fabrication by combined electron beam lithography and electrodeposition. PMID:21997000

Chen, Tsung-Yu; Chen, Yu-Tung; Wang, Cheng-Liang; Kempson, Ivan M; Lee, Wah-Keat; Chu, Yong S; Hwu, Y; Margaritondo, G

2011-10-10

91

Electron energy distributions from multiple ionization in 20-120keV H++Ar collisions  

Microsoft Academic Search

Energy-analyzed secondary electrons from H++Ar collisions at eight proton energies from 20 to 120 keV were detected in coincidence with recoil ions of charge states 1-3. The charge states were distinguished by time-of-flight measurements and the electron energies were analyzed by a newly designed electrostatic analyzer of the low-pass high-pass filter type which has a large (~1.45pi steradian) solid angle

Yang-Soo Chung; M. E. Rudd

1996-01-01

92

Spectral measurements of galactic and extragalactic sources in the hard X-ray region of 20-200 keV using balloon borne telescope  

Microsoft Academic Search

The spectral and temporal measurements in the hard X-ray region between 20-200 keV not only determines the extended behaviour of thermal X-ray spectrum below 10 keV but also provide a unique insight into the non-thermal processes in relativistic astrophysical plasma. From our present understanding of the X-ray sources, a significant flux in the 20-200 keV band is expected from a

R. K. Manchanda

2002-01-01

93

Impulsive 2-10 keV solar electron events not associated with flares  

NASA Astrophysics Data System (ADS)

Data from the ISEE 3 satellite reveal a class of impulsive solar electron events with no measurable increase in flux above 10-20 keV. The flux histories and angular distributions indicate that the electrons propagate through interplanetary space with little or no scattering. The smooth extension of the power-law energy spectra down to the limit of the observations at 2 keV indicates that the electrons are accelerated at altitudes greater than 0.5 solar radii in the solar corona. Although these events occur more frequently than any other type of impulsive solar particle event observed, no correlation is found with flares or flare-related activity. However, there is a close correlation with low-frequency type III radio bursts.

Potter, D. W.; Lin, R. P.; Anderson, K. A.

1980-03-01

94

Tomographic imaging based on scattered radiation from polyethylene using 10, 15, 20, 25 and 30 keV synchrotron X-rays with simple approximations  

Microsoft Academic Search

Tomographic imaging based on scattered radiation from polyethylene (C5H8O2), is evaluated, using 10, 15, 20, 25 and 30keV synchrotron X-rays. The SYRMEP facility at Elettra, Trieste, Italy, has been used to detect the scattered radiation from the sample at an angle of 90 using Si-Pin detector coupled to a multi-channel analyzer. The contribution of transmitted, Compton and fluorescence photons are

D. V. Rao; T. Yuasa; T. Akatsuka; G. Tromba; M. Zahid Hasan; T. Takeda

2005-01-01

95

Cross Section for Excitation of the Fourth Positive Band System in Carbon Monoxide by 20-120 keV Protons  

Microsoft Academic Search

Excitation cross sections for the fourth positive band system in carbon monoxide have been determined from studies of the energy-loss spectra of 20-120-keV protons incident on gaseous CO targets. The energy-loss spectra had an energy resolution of about 2 eV. Prominent peaks in the spectra were observed at 8.5 and 13.8 eV. The first peak is believed to be due

John T. Park; D. R. Schoonover; George W. York

1970-01-01

96

Multipoint observations of ions in the 30-160 keV energy range upstream of the Earth's bow shock  

NASA Astrophysics Data System (ADS)

We use multipoint observation data by Cluster during time periods when the interspacecraft separation distance was between 1 and 1.5 Earth radii in order to study the physical processes related to diffuse ions at <200 keV/e. For our analysis we use data from the Research with Adaptive Particle Imaging Detectors (RAPID) experiment onboard Cluster SC1 and SC3. We determine spatial ion density gradients by using proton intensities in the 27.7-159.7 keV energy range and helium intensities in the 137.8-235.1 keV energy range as a function of distance from the bow shock along the magnetic field. Our results show that the diffuse ions are subject to diffusive transport and the ion partial densities decrease exponentially with increasing distance from the bow shock. By complementing RAPID data with Cluster Ion Spectrometry measurements at lower energies (from 10 to 32 keV) from the same upstream ion event we find that the e-folding distance of energetic ion density increases almost linearly with energy. This effect is also seen in the hardening of the particle spectra with increasing distance from the bow shock. We determine the spatial diffusion mean free path and the diffusion coefficient as a function of ion energy by assuming that upstream diffusion is balanced by downstream convection.

Kronberg, E. A.; Kis, A.; Klecker, B.; Daly, P. W.; Lucek, E. A.

2009-03-01

97

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

SciTech Connect

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.

Gaines, J.L.; Wittmayer, F.J.

1986-06-01

98

Detection of 10-20 keV H+, He+ ions and electrons by planar oxide passivated and ion implanted silicon diodes  

NASA Astrophysics Data System (ADS)

A low noise UV-enhanced silicon photodiode has been modified into a low energy particle detector by removing the antireflection oxide layer. The electronic noise of a 100 mm2 device and a conventional charge sensitive preamplifier has been measured to 2.3 keV FWHM at room temperature operation. The response of this detector to low energy particles has been investigated. Electrons with 10 keV initial energy looses 0.8 keV in the surface deadlayer. Further, the sum of the energy losses in the deadlayer and to nuclear collisions have been measured to about 3.8 keV for 10 keV protons and 5.4 keV protons and 5.4 keV for 12 keV He+ ions

Johansen, G. A.; Stadsnes, J.; Sraas, F.; Hansen, T. E.

1991-11-01

99

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

NASA Astrophysics Data System (ADS)

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 20 keV. 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 133.2 K is deduced to be 52056 eV. 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 ?(E) and the experimental S(E) factor for D(d,p)T reaction in Sm metal at 133.2 K are obtained, respectively.

Wang, Tie-Shan; Yang, Zhen; Yunemura, H.; Nakagawa, A.; Lv, Hui-Yi; Chen, Jian-Yong; Liu, Sheng-Jin; Kasagi, J.

2007-11-01

100

Measurement of mass attenuation coefficients of some boron compounds and the trommel sieve waste in the energy range 15.746 40.930 keV  

Microsoft Academic Search

Mass attenuation coefficients of some boron compounds (H3BO3,Na2B4O7 and B3Al2O3) and the trommel sieve waste (TSW) have been measured by using an extremely narrow collimated-beam transmission method in the energy range 15.74640.930keV. The characteristic K? and K? X-rays of Zr, Mo, Ag, In, Sb, Ba and Pr passed through H3BO3,Na2B4O7, B3Al2O3 and TSW were detected with a high-resolution Si(Li) detector.

Orhan ?elli; Salih Erzeneo?lu; Recep Boncukuo?lu

2003-01-01

101

Two-photon above-threshold ionization of hydrogen over the photon energy range from 15 eV to 50 keV  

SciTech Connect

We investigate the absorption of two identical photons from the ground state of hydrogen-like atoms over an energy range that extends beyond that explored up to now. Our approach is based on a hybrid formula, valid in second-order perturbation theory, in which the A{sup 2} contribution from the nonrelativistic Hamiltonian is treated exactly, while the A{center_dot}P contribution is calculated in dipole approximation. We find that, at least up to 50 keV, the nonrelativistic dipole approximation, based only on the A{center_dot}P contribution, determines the values of the total cross section. Our numerical results, covering photon energies from 90 nm (13.7 eV) to 0.0248 nm (50 keV) are in very good agreement with most previous theoretical works. Differences with recent results are discussed.

Florescu, Viorica; Budriga, Olimpia; Bachau, Henri [Department of Physics and Centre for Advanced Quantum Physics, University of Bucharest, MG-11, R-077125 Bucharest-Magurele (Romania); National Institute for Laser, Plasma and Radiation Physics, R-077125 Bucharest-Magurele (Romania); Centre des Lasers Intenses et Applications, Universite Bordeaux I-CNRS-CEA, F-33405 Talence Cedex (France)

2011-09-15

102

Determination of HPGe detector response using MCNP5 for 20-150 keV X-rays.  

PubMed

The Monte Carlo method was used to calculate the efficiency, escape and Compton curves of a planar high-purity germanium detector (HPGe) in the 20-150 keV energy. These curves were used for the determination of photons spectra produced by an X-ray machine in order to allow a precise characterization of photon beams applied to medical diagnosis. The detector was modeled with the MCNP5 computer code and validated by comparison with experimental data. The air kerma calculated after the spectra stripping was compared with ionization chamber measurements. PMID:16427294

Salgado, Csar Marques; Conti, Claudio C; Becker, Paulo H B

2006-01-19

103

A miniature and ultralow power search coil optimized for a 20 mHz to 2 kHz frequency range  

NASA Astrophysics Data System (ADS)

We describe the design of a miniature search-coil magnetometer that is optimized in terms of resolution and power consumption for frequencies down to 20 mHz. Our aim is to come close to the size and resolution of fluxgate magnetometers, while reducing the power consumption by at least an order of magnitude. To reach this goal, we attach flux concentrators in the shape of thin disks to a ferrite core, employ an ultralow power, zero 1/f noise preamplifier, and finally optimize the diameters of the coil core and wire. The optimized search coil is of 54 mm length, 30 mm outer diameter, and includes 160 000 turns of a 50 ?m copper wire. The coil resistance is 86 k?, the self-resonance frequency is 250 Hz, and the total weight is 210 g. Our experimental results are in close agreement with the theoretical calculations. For a power consumption of 5 mW, the coil resolution is 14 pT/?Hz at 1 Hz and reaches 350 fT/?Hz in the frequency range from 100 Hz to 2 kHz. For a power consumption of 0.17 mW, the coil resolution decreases only by 25%. As a result, the new search-coil magnetometer consumes power one to two orders of magnitude less than the commercial fluxgates having similar resolution and size.

Paperno, Eugene; Grosz, Asaf

2009-04-01

104

Thermodynamic properties of fluid /sup 4/He in the 75 to 300/sup 0/K and 2- to 20-kbar range  

SciTech Connect

Helium is the simplest noble gas and is the second most abundant element in the universe. Helium properties are required for the use of helium in energy technologies, basic physical research studies, and astrophysical modeling. This report summarizes new pressure, volume, temperature, and sound velocity measurements on /sup 4/He in the ranges 75 to 300/sup 0/K and 2 to 20 kbar. From an equation of state (EOS) fitted to these data, are calculated and tabulated the thermodynamic quantities: volume V, sound velocity v/sub s/, thermal expansivity ..cap alpha../sub p/, heat capacity at constant pressure C/sub p/, the ratio of specific heats ..gamma.., adiabatic compressibility chi/sub s/, and molar entropy S. Computer-drawn graphs of the isothermal pressure variation of these quantities are presented and the precision of the fits to the data is discussed. Comparison with other measurements is described in the limited region of overlap, that is, at less than 10 kbar and near room temperature.

Liebenberg, D.H.; Mills, R.L.; Bronson, J.C.

1980-10-01

105

Marketing 2.0  

ERIC Educational Resources Information Center

|There is no doubt that today's student is much more savvy with using computers than the students of years gone by. This tech generation eagerly embraces the Internet, online searching, and the newer Web 2.0 technologies. This latter platform provides users with the ability to interact in a large virtual world, share/take (upload/download)

Germain, Carol Anne

2008-01-01

106

Marketing 2.0  

ERIC Educational Resources Information Center

There is no doubt that today's student is much more savvy with using computers than the students of years gone by. This tech generation eagerly embraces the Internet, online searching, and the newer Web 2.0 technologies. This latter platform provides users with the ability to interact in a large virtual world, share/take (upload/download)

Germain, Carol Anne

2008-01-01

107

The gyromagnetic ratio of the 589 keV 3\\/2 ? state of 117 In  

Microsoft Academic Search

Theg-factor of the 589 keV state of117In has been determined by a measurement of the rotation of the 1,303273 keV? ? directional correlation in an external magnetic field of 9.55(1) T. The result,g3\\/2(589 keV)=+0.068(39), contradicts the usual interpretation of the state as the 2p3\\/2 single proton hole configuration for which the Schmidt value isg3\\/2-(Schmidt)=+2.53. It favours the interpretation as the

A. Alzner; E. Bodenstedt; B. Gemnden; H. Reif

1985-01-01

108

Fracture behavior of a B2 Ni30Al20Fe0.05Zr intermetallic alloy in the temperature range 300 to 1300 K  

Microsoft Academic Search

Tensile tests were conducted on a Ni-30 (at. pct) Al-20Fe-0.05Zr intermetallic alloy in the temperature range 300 to 1300\\u000a K under initial strain rates varying between 10?6 and 10?3 s?1. The alloy did not exhibit any room-temperature ductility and failed at an average stress of about 710 MPa. The brittle-to-ductile\\u000a transition temperature (BDTT), which was higher than those for Ni-50Al

S. V. Raj

1992-01-01

109

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

NASA Astrophysics Data System (ADS)

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 3 keV but has reduced sensitivity above 3 keV (~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.

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

2006-10-01

110

Emission Lines between 1 and 2 keV in Cometary X-Ray Spectra  

NASA Astrophysics Data System (ADS)

We present the detection of new cometary X-ray emission lines in the 1.0-2.0 keV range using a sample of comets observed with the Chandra X-Ray Observatory and ACIS spectrometer. We have selected five comets from the Chandra sample with good signal-to-noise spectra. The surveyed comets are C/1999 S4 (LINEAR), C/1999 T1 (McNaught-Hartley), 153P/2002 (Ikeya-Zhang), 2P/2003 (Encke), and C/2008 8P (Tuttle). We modeled the spectra with an extended version of our solar wind charge exchange (SWCX) emission model. Above 1 keV, we find Ikeya-Zhang to have strong emission lines at 1340 and 1850 eV which we identify as being created by SWCX lines of Mg XI and Si XIII, respectively, and weaker emission lines at 1470, 1600, and 1950 eV formed by SWCX of Mg XII, Mg XI, and Si XIV, respectively. The Mg XI and XII and Si XIII and XIV lines are detected at a significant level for the other comets in our sample (LS4, MH, Encke, 8P), and these lines promise additional diagnostics to be included in SWCX models. The silicon lines in the 1700-2000 eV range are detected for all comets, but with the rising background and decreasing cometary emission, we caution that these detections need further confirmation with higher resolution instruments.

Ewing, Ian; Christian, Damian J.; Bodewits, Dennis; Dennerl, Konrad; Lisse, Carey M.; Wolk, Scott J.

2013-01-01

111

Evolution of nucleon structure functions in the Q2 range between 20 and 10 000 GeV2 from a new QCD analysis of neutrino data  

NASA Astrophysics Data System (ADS)

From the nucleon structure functions measured by the CHARM Collaboration in inclusive neutrino and antineutrino CC interactions we determined the QCD parameters ?MS = 310 +/- 140 (stat.) +/- 70(syst.) MeV using the Furmanski- Petronzio method. With the same method we extrapolated the behaviour of the quark (q + q) and the gluon x-distributions up to Q2 = 10 000 GeV2 using perturbative QCD. The extrapolated structure functions are compared with recent results coming from the two-jet differential cross section in proton-antiproton interactions at ?s = 540 GeV and Q2 = 2000 GeV2. Laboratori Nazionali INFN Frascati, Frascati, Italy.

Bergsma, F.; Dorenbosch, J.; Allaby, J. V.; Amaldi, U.; Barbiellini, G.; Flegel, W.; Lanceri, L.; Metcalf, M.; Nieuwenhuis, C.; Panman, J.; Santoni, C.; Winter, K.; Abt, I.; Aspiazu, J.; Bsser, F. W.; Daumann, H.; Gall, P. D.; Hebbeker, T.; Niebergall, F.; Schtt, P.; Sthelin, P.; Gorbunov, P.; Grigoriev, E.; Khovansky, V.; Rosanov, A.; Baroncelli, A.; Barone, L.; Borgia, B.; Bosio, C.; Capone, A.; Diemoz, M.; Dore, U.; Ferroni, F.; Longo, E.; Luminari, L.; Monacelli, P.; de Notaristefani, F.; Tortora, L.; Valente, V.

1985-03-01

112

Mass attenuation coefficient of the Earth, Moon and Mars samples over 1keV-100GeV energy range.  

PubMed

This work presents the calculation of the mass attenuation coefficient (micro) of lunar, Martian and terrestrial samples in function of the energy. WinXCOM software was employed to determine the micro values for the samples in the range from 1 keV to 100 GeV. The obtained values were practically the same for energies larger than 100 keV, but marked differences among the samples were observed for energies below 25 keV, which is the energy range of interest for the XRF system used in space probes. PMID:16725330

Camargo Moreira, Anderson; Roberto Appoloni, Carlos

2006-05-24

113

Spectral measurements of galactic and extragalactic sources in the hard X-ray region of 20-200 keV using balloon borne telescope  

Microsoft Academic Search

The spectral and temporal measurements in the hard X-ray region between 20-200 keV not only determines the extended behaviour\\u000a of thermal X-ray spectrum below 10 keV but also provide a unique insight into the non-thermal processes in relativistic astrophysical\\u000a plasma. From our present understanding of the X-ray sources, a significant fluxin the 20-200 keV band is expected from a variety

R. K. Manchanda

2002-01-01

114

Specification of the plasma environment at geosynchronous orbit in the energy range 87 eV to 288 keV  

SciTech Connect

The particle measurements by the P78-2 SCATHA satellite at near geosynchronous altitudes have been analyzed to obtain average electron and proton fluxes in the energy range 87 eV to 288 keV. The variation of the fluxes about the average values is also reported and the average fluxes are compared to those measured during an intense spacecraft charging event on September 22, 1982. These calculations provide a representation of the plasma environment, which can be used to quantify the surface charging of spacecraft materials in geosynchronous orbit.

Roeder, J.L.

1994-08-15

115

Directional Bremsstrahlung from a Ti Laser-Produced X-Ray Source at Relativistic Intensities in the 3-12 keV Range  

SciTech Connect

Front and rear side x-ray emission from thin titanium foils irradiated by ultraintense laser pulses at intensities up to {approx_equal}5x10{sup 19} W/cm{sup 2} was measured using a high-resolution imaging system. Significant differences in intensity, dimension, and spectrum between front and rear side emission intensity in the 3-12 keV photon energy range was found even for 5 {mu}m thin Ti foils. Simulations and analysis of space-resolved spectra explain this behavior in terms of directional bremsstrahlung emission from fast electrons generated during the interaction process.

Zamponi, F.; Luebcke, A.; Kaempfer, T.; Uschmann, I.; Foerster, E. [Institut fuer Optik und Quantenelektronik, Friedrich-Schiller-Universitaet Jena, Max-Wien-Platz 1, 07743 Jena (Germany); Robinson, A. P. L. [Central Laser Facility, STFC Rutherford-Appleton Laboratory, Chilton, OX11 0QX (United Kingdom); Giulietti, A.; Koester, P.; Labate, L.; Levato, T.; Gizzi, L. A. [ILIL, Istituto Nazionale di Ottica, UOS 'Adriano Gozzini', CNR, Via G. Moruzzi 1, Pisa (Italy); INFN, Sezione di Pisa, Largo B. Pontecorvo 3, Pisa (Italy)

2010-08-20

116

Importance of L=2 components in the 2H(d,n)3He reaction for deuteron energies below 350 keV  

Microsoft Academic Search

Angular distributions for the 2H(d,n)3He reaction have been calculated for incident deuteron energies between 19.5 keV and 349 keV. Model calculations are performed using the generalised R-matrix methodology of Lane and Robson (1966) and additional distorted wave Born approximation terms to describe the long-range spatial contribution to the cross section. Model results are consistent with the experimental prediction of Galloway

J. J. Bevelacqua

1981-01-01

117

Axial and radial coefficients of thermal expansion of carbon fibers in the 20-430 C temperature range as derived from the thermal expansion of 1-D-C-SiO2(B2O3) composites  

Microsoft Academic Search

The axial and radial coefficients of thermal expansion (CTE) of HS (T300), HM (M40), and UHM (P100) carbon fibers have been computed, within the 20-430 C temperature range, from thermal expansion measurements performed on unidirectional composites with the fibers embedded in an isotropic glass SiO2-15 mol pct B2O3 matrix. The various CTE of the carbon fibers were found to be

E. Menessier; J. P. Dumont; A. Geutte; R. Pailler; L. Rabardel

1989-01-01

118

Iridium optical constants from x-ray transmission measurements over 2 to 12 keV  

NASA Astrophysics Data System (ADS)

Precise transmission measurements of free standing iridium foils and of iridium coatings supported on thin polyimide film have been made at the X8 beamline of the National Synchrotron Light Source, at energies from 2 to 12 keV. These measurements were conducted to provide iridium optical constants in support of NASA's Advanced X-ray Astrophysics Facility (AXAF). Transmission data were collected at small energy increments across iridium M and L absorption edges to study detailed edge structures. From these data, the imaginary components of the index of refraction were computed. The data also allows computation of the real parts, using the Kramers-Kronig dispersion integral. Preliminary results indicate a measurement accuracy of better than one percent for transmission. Absorption coefficients deviate by varying amounts from values predicted from Henke data table, which is consistent with the accuracy claimed for those table.s Nonuniform thickness in our iridium foils may be a source of errors in our analysis and improved foils are being sought. Additional measurements will also be needed with foils of different thickness to account and correct for possible effects of sample thickness on the determination of absorption edge fine structure. To our knowledge, transmission measurements of this degree of accuracy and precision have not been previously reported in the literature for iridium in the 2- 12 keV energy range.

Harris, Bernard; Graessle, Dale E.; Fitch, J. J.; Juda, Jiahong Z.; Blake, Richard L.; Schattenburg, Mark L.; Gullikson, Eric M.

1996-07-01

119

Inferno 2.0  

NSDL National Science Digital Library

Inferno, created at Lucent Technologies' Bell Labs, is a new operating system that could be the "Unix for the next century." Created by the same research lab that invented C++ and Unix, Inferno's primary goal is to operate seamlessly within a heterogeneous network environment. By abstracting resource interfaces to a common format, Inferno provides a general way to access all resources, both local and remote. Beyond that, the operating system is portable across many platforms and networks, and applications written in Limbo, the Inferno programming language, are also portable and lightweight. Impossible to describe in a single paragraph, the Inferno operating system is a fascinating leap ahead in networking and systems technology. Inferno is useful for research, development, learning, and many other possibilities. Freely available, Inferno 2.0 runs on Win95/NT, Solaris, and Linux.

1998-01-01

120

High Spatial Resolution STXM at 6.2 keV Photon Energy  

SciTech Connect

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.

Vila-Comamala, Joan; Kewish, Cameron M.; Thibault, Pierre; Guzenko, Vitaliy; Gorelick, Sergey; Menzel, Andreas; Bunk, Oliver; David, Christian [Paul Scherrer Institut, CH-5232 Villigen (Switzerland); Dierolf, Martin; Pfeiffer, Franz [Technische Universitaet Muenchen, D-85748 Garching (Germany); Pilvi, Tero; Faerm, Elina; Ritala, Mikko [Department of Chemistry, FI-00014 University of Helsinki (Finland)

2010-04-06

121

Swelling effects in Y2Ti2O7 pyrochlore irradiated with 400 keV Ne2+ ions  

NASA Astrophysics Data System (ADS)

Polycrystalline pyrochlore Y2Ti2O7 compounds were irradiated with 400 keV Ne2+ ions at cryogenic temperature (77 K) at fluences ranging from 5 1014 to 1 1016 ions/cm2, corresponding to a peak ballistic damage dose of 0.17-3.4 displacements per atom (dpa). Irradiation-induced structural evolution was examined using grazing incidence X-ray diffraction at X-ray incident angles from 0.25 to 3 and cross-sectional transmission electron microscopy. An apparent swelling effect was observed on the irradiation layer prior to the irradiated layer being amorphized. The swelling effect increased with increasing ion irradiation fluence. At an ion induced damage of 1.7 dpa, the irradiated layer started to be amorphized.

Li, Y. H.; Wang, Y. Q.; Valdez, J. A.; Tang, M.; Sickafus, K. E.

2012-03-01

122

Web 2.0, Meet Literacy 2.0  

ERIC Educational Resources Information Center

|In this article, Literacy 2.0 is defined in terms of Web 2.0 influences. Literacy 2.0 encompasses several major characteristics that distinguish it from traditional literacy practices (Literacy 1.0). For educational technology professionals, Literacy 2.0 skills become a critical means for developing lifelong learning.|

Penrod, Diane

2008-01-01

123

Optimum condition of efficiency functions for HPGe ?-ray detectors in the 121-1408 keV energy range  

NASA Astrophysics Data System (ADS)

The optimum condition of three commonly used functions in the Genie 2000 ? spectra analysis software have been studied in the 121-1408 keV energy range. The three functions are applied for fitting the full-energy peak efficiency of the HPGe gamma-ray detector. A detailed procedure to obtain the optimum condition is described. The HPGe detector is calibrated at 11 cm by three radioactive sources of point form (152Eu, 137Cs, 60Co) providing 11 energy peaks. After data processing, results shows that the three functions used in the Genie 2000 gamma spectra analysis software fit best at orders 3-5. Lastly the standard radioactive source 133Ba is chosen to validate the results. Differences between the standard activity of 133Ba and the result obtained from the fitting functions are below 1.5%. Therefore the optimum orders of the three functions used in the Genie 2000 ? spectra analysis software are 3-5 with the 11 energy peaks.

Chen, Zhi-Lin; Song, Guo-Yang; Mu, Long; Wang, He-Yi; Xing, Shi-Xiong; Guo, Hong-Bo; Liao, Zhen-Xing; Chen, Ping; Hua, Sheng

2010-05-01

124

Antiproton stopping power in He in the energy range 1900 keV and the Barkas effect  

Microsoft Academic Search

The p stopping power in helium from 1 keV kinetic energy is evaluated. Contrary to the effect observed around and below the maximum, Obelix data indicate a p stopping power higher than that for proton, the difference being of the order of 155% at ?700 keV. The result contributes to assert the fundamental difference between p stoppings in the simplest

E. Lodi Rizzini; A. Bianconi; M. P. Bussa; M. Corradini; A. Donzella; M. Leali; L. Venturelli; N. Zurlo; M. Bargiotti; A. Bertin; M. Bruschi; M. Capponi; S. De Castro; R. Don; L. Fabbri; P. Faccioli; B. Giacobbe; F. Grimaldi; I. Massa; M. Piccinini; N. Semprini Cesari; R. Spighi; S. Vecchi; M. Villa; A. Vitale; A. Zoccoli; O. E. Gorchakov; G. B. Pontecorvo; A. M. Rozhdestvensky; V. I. Tretyak; M. Poli; C. Guaraldo; C. Petrascu; F. Balestra; L. Busso; O. Y. Denisov; L. Ferrero; R. Garfagnini; A. Grasso; A. Maggiora; G. Piragino; F. Tosello; G. Zosi; G. Margagliotti; L. Santi; S. Tessaro

2004-01-01

125

Linear optical properties of (Cu2O)x (Al2O3)0.05-x (B2O3)0.20 (PbO)0.75 glasses in the spectral range 200-3300 nm  

NASA Astrophysics Data System (ADS)

Glasses of composition (Cu2O)x (Al2O3)0.05-x (B2O3)0.20 (PbO)0.75, where x = 0.0, 0.005, 0.0075, 0.01, 0.02, 0.035, and 0.05, are prepared using the normal melt quench technique. Reflectance and transmittance at normal incidence are measured by a spectrophotometer in the spectral range of 200-3300 nm. Analytical relations are used to deduce the real and imaginary refractive indices, at each scanned wavelength, from the measured reflectance and transmittance. Dispersive parameters of Wemple-DiDomenico dispersion's relation, molar refraction and molar polarizability are deduced. Direct and indirect allowed transitions optical energy gaps are calculated from the absorption coefficients. Effects of substituting Al2O3 by Cu2O, on these linear optical properties of the prepared glasses are studied. The prepared glasses can be used as near IR filters with 70% transmittance.

El-Naggar, A. M.; El-Zaiat, S. Y.; Youssif, M. I.; Alsaud, F. A.

2013-10-01

126

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

PubMed

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

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

2006-05-30

127

Measurement of the exp 6 Li (N, alpha )T Cross-Section over the Energy Range 150 Kev to 3.9 Mev.  

National Technical Information Service (NTIS)

A measurement has been made of the exp 6 Li(n, alpha )t cross section sigma/sub n alpha/ in the energy range 160 keV to 3.9 MeV by calibrating a exp 6 Li semiconductor sandwich spectrometer against counters of known relative efficiencies. As a result of t...

P. J. Clements I. C. Rickard

1972-01-01

128

High-resolution integrated germanium Compton polarimeter for the ?-ray energy range 80 keV1 MeV  

Microsoft Academic Search

Parameters which govern the choice of a detection system to measure the linear polarization of ? 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

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

1995-01-01

129

Structure of Ba(Y(1/2)(+3)Ta(1/2)(+5))03 and its dielecrtric properties in the range 10(exp 2) to 10(exp 14) Hz, 20-600 K  

NASA Astrophysics Data System (ADS)

The goal of this work was to understand the correlation between microscopic material parameters and the dielectric function of candidate materials for applications in the microwave frequency range. The structure and dielectric properties of Ba(2+)(Y(1/2)(3+)Ta(1/2)(5+))03 (BYT), a typical representative of the Ba(B(1/2)(3+)B(1/2)(5+))03 complex perovskite family, has been investigated from 10(exp 2) to 10(exp 14) Hz and from 20 to 600 K. At T(sub c) = 253 +/- 1 K, BYT undergoes an equitranslational improper ferroelastic, second-order phase transition, characterized by the tilting of the oxygen octahedra. The space group symmetry changes from Fm(3-bar)m, in the high temperature phase, to I4/m below T(sub c). The existence of an intermediate temperature region ((T(sub c) - 40) less than T less than T(sub c)) has been observed, where the compound exhibits structural and dielectric properties different from those in the well-defined high (T greater than T(sub c)) and low (T less than (T(sub c) - 40) K) temperature phases. Infrared reflectivity (10(exp 12) to 10(exp 14) Hz) and submillimeter transmission (10(exp 11) to 3 x 10(exp 12) Hz) measurements yield dielectric losses which are believed to be mainly of intrinsic origin (one- and two-phonon absorption). Comparing a theory of two-phonon difference absorption processes, due to thermally activated polar branches, with the loss measured at 400-1400 GHz, the intrinsic loss can be extrapolated to lower frequencies. At 10 GHz the extrapolated value is about 1/4 of the loss actually measured in a BYT resonator. The temperature dependencies indicate the soft branch to be of considerable importance for intrinsic losses. Oxygen vacancies can be excluded as an extrinsic loss source, as sintering and annealing in N2, air, and O2 had no measurable influence on the loss at 10 GHz.

Zurmuehlen, R.; Colla, E.; Dube, D. C.; Petzelt, J.; Reaney, I.; Bell, A.; Setter, N.

1994-11-01

130

BASINS 2.0  

NSDL National Science Digital Library

The Environmental Protection Agency (EPA) first created BASINS (Better Assessment Science Integrating Point and Nonpoint Sources) in 1996 as an aid to water resource planners concerned with water quality and watershed analyses. The strength of BASINS is its integration of \\"a geographic information system (GIS), national watershed data, and state-of-the-art environmental assessment and modeling tools.\\" The updated version of the program, BASINS 2, can be downloaded from this site.

2005-11-01

131

BASINS 2.0  

NSDL National Science Digital Library

The Environmental Protection Agency (EPA) first created BASINS (Better Assessment Science Integrating Point and Nonpoint Sources) in 1996 as an aid to water resource planners concerned with water quality and watershed analyses. The strength of BASINS is its integration of "a geographic information system (GIS), national watershed data, and state-of-the-art environmental assessment and modeling tools." The updated version of the program, BASINS 2, can be downloaded from this site.

1998-01-01

132

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

NASA Astrophysics Data System (ADS)

The effective atomic numbers and electron densities of YBa2Cu3O7-? 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-? superconductor is close to the theoretical structure. Zeff and Nel experimental values showed good agreement with the theoretical values for calcined and sintered YBa2Cu3O7-?.

Balta?, H.; evik, U.

2008-04-01

133

Modeling of synchrotron reflectance calibrations of AXAF iridium-coated witness mirrors over 2 to 12 keV  

NASA Astrophysics Data System (ADS)

As calibrations of AXAF mirrors in the 2-12 keV range are near completion, we can report that the archive is complete for the scheduled number of mirrors over the 5-12 keV range, and also over the 2010-6200 eV range. Analysis of the results for optical constants and coating layer parameters is now proceeding rapidly. To date, we have derived optical constants from 39 mirrors over 5-12 keV using our existing Fresnel Equation model, with uniform layers of Ir, Cr, and Zerodur, and the roughness algorithm of Nevot and Croce. The analysis method has been presented in our earlier papers, but its application has been expanded to all three varieties of witness mirrors use in AXAF's qualification and production coating runs. For the first and most consistent variety, which have 1 angstrom roughness, reflectances are indistinguishable from mirror to mirror save for thickness variations between coating runs. Residuals of the fits for optical constants become large when reflectance values below 18 percent are included in the fits. If such data points are ignored, values of (delta) (E) and (beta) (E) very much like those of Henke et al. over 5-11 keV are obtained. Residuals are at the 0.6-0.8 percent level, which meets calibration requirements but exceeds experimental noise. For the second variety of witness mirror, polished to obtain roughness specification similar to the flight mirrors, fits approximately within the noise level of the measurements may be obtained over 5-11 keV, for reflectance values down to 5 percent. The (delta) (E) is essentially the same as that obtained from the 1 angstrom flats; however (beta) (E) is higher by approximately 3-4 percent systematically, and the mirror-to-mirror variation is larger. The third variety of mirror was obtained with 5-7 angstrom nominal roughness. Residuals to the fits are large for the entire range of angles, in some case exceeding 2 percent with a sinusoidal character through the critical angle. Coating layer depths are similar to those found for the other mirror types, with good precision. We discuss results along with possible improvements to the model and experiments to verify it.

Graessle, Dale E.; Blake, Richard L.; Burek, Anthony J.; Dyson, S. E.; Fitch, Jonathan J.; Schwartz, Daniel A.; Soufli, Regina

1998-11-01

134

Hydrodynamic study of plasma amplifiers for soft-x-ray lasers: a transition in hydrodynamic behavior for plasma columns with widths ranging from 20 ?m to 2 mm.  

PubMed

Plasma-based seeded soft-x-ray lasers have the potential to generate high energy and highly coherent short pulse beams. Due to their high density, plasmas created by the interaction of an intense laser with a solid target should store the highest amount of energy density among all plasma amplifiers. Our previous numerical work with a two-dimensional (2D) adaptive mesh refinement hydrodynamic code demonstrated that careful tailoring of plasma shapes leads to a dramatic enhancement of both soft-x-ray laser output energy and pumping efficiency. Benchmarking of our 2D hydrodynamic code in previous experiments demonstrated a high level of confidence, allowing us to perform a full study with the aim of the way for 10-100 ?J seeded soft-x-ray lasers. In this paper, we describe in detail the mechanisms that drive the hydrodynamics of plasma columns. We observed transitions between narrow plasmas, where very strong bidimensional flow prevents them from storing energy, to large plasmas that store a high amount of energy. Millimeter-sized plasmas are outstanding amplifiers, but they have the limitation of transverse lasing. In this paper, we provide a preliminary solution to this problem. PMID:21230603

Oliva, Eduardo; Zeitoun, Philippe; Velarde, Pedro; Fajardo, Marta; Cassou, Kevin; Ros, David; Sebban, Stephan; Portillo, David; le Pape, Sebastien

2010-11-12

135

Formation of doubly charged potassium ions in K+-He and K+-Kr collisions in the 1-10 keV energy range  

NASA Astrophysics Data System (ADS)

We present measurements of the absolute total cross-sections for the formation of K2+ ions, the production of free electrons and the excitation of K+, Ko, He and Kr particles in K+-He and K+-Kr collisions at moderate energies (1-10 keV). The formation mechanisms of K2+ ions are discussed.

Gochitashvili, M.; Kikiani, B.; Lomsadze, R.

2003-05-01

136

Large Goldanskii effect in quadrupole Mossbauer spectra of the 103.2 keV gamma ray of 153Eu  

Microsoft Academic Search

A large Goldanskii effect was observed in the recoilless absorption spectra of the 103.2 keV gamma ray of 153Eu in Eu2Ti2O7. Values for the quadrupole interaction parameters, the crystal field parameter V02 keV gamma ray of 153Eu and the shielding parameter sigma2 were deduced.

H. Armon; E. R. Bauminger; A. Diamant; I. Nowik; S. Ofer

1973-01-01

137

/sup 2/H(. gamma. ,n) absolute cross section at 2754 keV  

SciTech Connect

The absolute cross section of the photodisintegration of deuterium was measured at 2754 keV using an absorptive method by passing the photons through 2-m-long absorbers of H/sub 2/O and D/sub 2/O. The measured value is 1456 +- 45 ..mu..b. The result is compared with calculations that include contributions from meson-exchange currents and isobar configurations.

Moreh, R.; Kennett, T.J.; Prestwich, W.V.

1989-04-01

138

Measurements of photon-atom elastic scattering cross-sections in the photon energy range 1 keV to 4 MeV  

Microsoft Academic Search

We review the current status of measurements of photon-atom elastic scattering cross-sections for the restricted photon energy range 1 keV up to 4 MeV. Among the key experimental factors which influence the accuracy and precision of a particular type of measurement are the choice of source, detector and scattering geometry. We have examined the interests which motivate the making of

D. A. Bradley; O. D. Goncalves; P. P. Kane

1999-01-01

139

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

Microsoft Academic Search

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

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

2005-01-01

140

Measurement of the subthreshold neutron fission cross section of plutonium-240 in the energy range from 10 to 250 keV. [Cross section structure  

Microsoft Academic Search

The subthreshold fission cross section of ²⁴°Pu was measured in the energy range from 10 to 250 keV, using ²³⁵U as a standard. Neutrons were produced via the ⁷Li(p,n) and T(p,n) reaction with the Karlsruhe 3-MV pulsed Van de Graaff accelerator. Fission events were registered by detecting fission neutrons with an NE-213 liquid scintillator with pulse-shape discriminator equipment. The high

K. Wisshak; F. Kaeppeler

1979-01-01

141

Medical Librarian 2.0  

Microsoft Academic Search

Web 2.0 refers to an emerging social environment that uses various tools to create, aggregate, and share dynamic content in ways that are more creative and interactive than transactions previously conducted on the Internet. The extension of this social environment to libraries, sometimes called Library 2.0, has profound implications for how librarians will work, collaborate, and deliver content. Medical librarians

Elizabeth Connor

2007-01-01

142

Library Instruction 2.0  

ERIC Educational Resources Information Center

At the 2008 ALA Annual Conference, a wonderful Association of College and Research Libraries (ACRL) preconference was presented entitled "Library Instruction 2.0: Building Your Online Instruction Toolkit". The presentation was enlightening and provided numerous and valuable recommendations for Web 2.0 sites that can facilitate and enliven library

Bridgewater, Rachel; Deitering, Anne-Marie; Munro, Karen

2009-01-01

143

2.0 for Readers  

ERIC Educational Resources Information Center

|The world of readers' advisory (RA) is embracing many of the tools that collectively are referred to as Library 2.0. RA has long shared many of the beliefs supported by Library 2.0--well before there even was such a thing--including conversations with readers, valuing and empowering the experience of the reader, and near constant reevaluation of

Wyatt, Neal

2007-01-01

144

2keV filtered beam facility at the NBS reactor  

Microsoft Academic Search

A scandium filter that views a manganese scatterer has been installed in a through tube of the National Bureau of Standards Reactor (NBSR). The use of a resonant scatterer eliminates unwanted core neutrons and core gamma rays. This produces a pure 2-keV neutron beam with only 3 percent higher energy neutron contamination and a 1 mR\\/hr⁻¹ gamma-ray background. This should

I. G. Schroder; R. B. Schwartz; E. D. McGarry

1975-01-01

145

A multi-energy (2-60 keV) calibration of 200 ? m and 400 ?m diameter spectroscopic GaAs X-ray photodiodes  

NASA Astrophysics Data System (ADS)

Thin (2 ?m active layer) spectroscopic p+-i-n+ GaAs X-ray photodiodes of circular mesa geometry (200 ?m and 400 ?m diameter; one representative diode of each diameter) have been characterised for their energy response using high-purity X-ray fluorescence calibration samples excited by an X-ray tube, giving energies between 2.1 keV (Au M?1) and 21.18 keV (Pd K?1), and an 241Am radioisotope ?-ray source (26.3 keV, 59.5 keV). The photodiodes were operated uncooled at +33C. The 200 ?m diameter device's energy resolution (FWHM) was found to be constant (0.79 keV) and primarily limited by electronics noise at energies between 2.1 keV and 21.18 keV, but it broadened to 0.85 keV at 26.3 keV, and to 1 keV at 59.5 keV. The 400 ?m diameter device's energy resolution (FWHM) was constant (1.1 keV) for photon energies between 4.95 keV and 9.89 keV, but increased to 1.15 keV at 16.62 keV, 1.25 keV at 21.18 keV, 1.3 keV at 26.3 keV and 1.66 keV at 59.5 keV. The broadening of energy resolution (FWHM) observed in both cases is greater than can be attributed solely to increasing Fano noise and is hypothesised to be at least in part due to energy dependent charge trapping. However, for both types of device, the peak charge output from the devices was found to be linearly (R2 >= 0.9999) dependent on incident X-ray energy.

Barnett, A. M.; Lees, J. E.; Bassford, D. J.

2013-09-01

146

Study of characteristics of polar cap auroras in DMSP images. Final report, 1 Oct 78-31 Dec 79. [50 eV to 20 keV  

SciTech Connect

Energetic electron measurements from a particle detector on the DMSP/F2 satellite have been used to determine the corrected geomagnetic latitude (Lambda sub CGM) of the equatorward boundary of the auroral oval. The satellite was launched into a nearly sun-synchronous, polar orbit centered on the 0700-1900 MLT meridian. Due to the wobble of the dipole and a very slow precessional motion of the orbit more than 6000 boundary crossings could be studied in the 1600-2300 and 0400-1000 MLT sectors. The detectors, which have large geometric factors, look radially away from the earth and detect precipitating electrons with energies between 50eV and 20keV. In the evening sector the equatorward boundaries are precisely determined from the rise in the total electron flux. The morningside boundary cannot always be clearly delineated. Data were divided into one hour magnetic local time bins with about 400 samples per bin. In each of the MLT bins Lambda sub CGM was found to be linearly correlated to the Kp index. Regression values of Lambda sub CGM were projected to the magnetic equatorial plane using the Mead-Fairfield magnetic field model. The projected boundaries are not in good agreement with the injection boundaries of Mauk and McIlwain (1974).

Gussenhoven, M.S.

1980-02-29

147

Measurement of the mass attenuation coefficient for elemental materials in the range 6 < or = Z < or = 82 using X-rays from 13 up to 50 kev.  

PubMed

The mass attenuation coefficients for 22 high purity elemental materials (C, Al, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, Mo, Rh, Pd, Ag, Cd, In, Ta, Pt, Au, Pb) were measured in the X-ray energy range from 13 up to 50 keV using a high purity germanium detector with thin (50 microm) Be window and a variable-energy X-ray source. The measured values are compared with the theoretical ones obtained using the XCOM code and data base, as well as with other experimental data showing a general agreement within +/- 5%. The mass attenuation cross-sections were thus derived and compared with other experimental data available on the 1988 NBS database of X-ray attenuation cross-sections. The agreement is always within +/- 8%, but for a few points the discrepancies are up to +/- 18%. The data analysis has also shown that some measurements performed at 50.65 keV as well as at 36.65 keV are to be considered as new data for most of the measured materials. PMID:11545503

Angelone, M; Bubba, T; Esposito, A

2001-10-01

148

XMM-Newton Slew Survey in 2-10keV (Warwick+, 2012)  

NASA Astrophysics Data System (ADS)

Details of the sources which comprise the hard-band selected XSS extragalactic sample are given in the Table. The table provides the following information for each source: the XSS name; whether the source was also detected in the XSS soft band (1=yes, 0=no); the XSS hard band (2-10keV) flux and error on the flux (in units of 10-11ergs/cm2/s) ; the RA and Dec of the proposed counterpart; the name of the counterpart; the type of the counterpart; the redshift (if known). (1 data file).

Warwick, R. S.; Saxton, R. D.; Read, A. M.

2012-10-01

149

Detection of 10-20 keV H+, He+ ions and electrons by planar oxide passivated and ion implanted silicon diodes  

Microsoft Academic Search

A low noise UV-enhanced silicon photodiode has been modified into a low energy particle detector by removing the antireflection oxide layer. The electronic noise of a 100 mm2 device and a conventional charge sensitive preamplifier has been measured to 2.3 keV FWHM at room temperature operation. The response of this detector to low energy particles has been investigated. Electrons with

G. A. Johansen; J. Stadsnes; F. Sraas; T. E. Hansen

1991-01-01

150

Study of effective atomic number and electron density for tissues from human organs in the energy range of 1 keV-100 GeV.  

PubMed

Effective atomic numbers' (Z(eff)) effective electron density (N(el)) for human organs and tissues have been computed in the energy region of 1 keV to 100 GeV using WinXCOM. The computed data of Z(eff) and N(el) are tabulated. The computed values are compared with previous results. The computed data of Z(eff)and N(el)for almost all tissues (34 tissues of different human organs) in the given energy range are not available in literature and find application in radiotherapy and dosimetry. PMID:23274818

Manjunatha, H C; Rudraswamy, B

2013-02-01

151

Energy loss and angular dispersion of 2-200 keV protons in amorphous silicon  

NASA Astrophysics Data System (ADS)

The energy loss of 2-200 keV protons in thin amorphous silicon foils has been measured for projectiles transmitted in the forward direction and as a function of the exit angle. At the lowest energies, differences of up to 30% with recently published values are observed. Angular effects in the energy loss, at low and high energies, have been investigated. The low-energy results are reproduced by model calculations and Monte Carlo simulations, which indicate that the inelastic energy loss does not show a dependence upon the impact parameter in the low energy region. A fitting formula for the present energy loss values is provided.

Fam, M.; Lantschner, G. H.; Eckardt, J. C.; Arista, N. R.; Gayone, J. E.; Sanchez, E.; Lovey, F.

2002-06-01

152

Measurement of the 20 and 90 keV resonances in the 18O(p,alpha)15N reaction via the Trojan horse method.  

PubMed

The 18O(p,alpha)15N 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 18O(p,alpha)15N 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. PMID:18999593

La Cognata, M; Spitaleri, C; Mukhamedzhanov, A M; Irgaziev, B; Tribble, R E; Banu, A; Cherubini, S; Coc, A; Crucill, 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

2008-10-07

153

Measurement of the 20 and 90 keV Resonances in the {sup 18}O(p,{alpha}){sup 15}N Reaction via the Trojan Horse Method  

SciTech Connect

The {sup 18}O(p,{alpha}){sup 15}N 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 {sup 18}O(p,{alpha}){sup 15}N 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.

La Cognata, M.; Spitaleri, C.; Cherubini, S.; Crucilla, V.; Gulino, M.; Lamia, L.; Pizzone, R. G.; Puglia, S. M. R.; Rapisarda, G. G.; Romano, S.; Sergi, M. L.; Tumino, A. [INFN Laboratori Nazionali del Sud and DMFCI Universita di Catania, 95123 Catania (Italy); Mukhamedzhanov, A. M.; Tribble, R. E.; Banu, A.; Goldberg, V. Z.; Tabacaru, G.; Trache, L. [Cyclotron Institute, Texas A and M University, College Station, 77843 Texas (United States); Irgaziev, B. [GIK Institute of Engineering Sciences and Technology, Topi (23640), NWFP Pakistan (Pakistan); Coc, A. [CSNSM, CNRS/IN2P3 Universite Paris Sud, F-91405 Orsay (France)] (and others)

2008-10-10

154

Academic Leadership 2.0  

ERIC Educational Resources Information Center

|Academic Leadership 2.0 means making an administrative partnership with the faculty the cornerstone of an institution's culture. Administrators have to stop thinking of themselves as operating on a different level from the faculty. The fear many administrators have is that if they demonstrate their willingness to advocate for the faculty, the

Buller, Jeffrey L.

2013-01-01

155

ART: Surveying the Local Universe at 2-11 keV  

NASA Astrophysics Data System (ADS)

The Astronomical Rntgen Telescope (ART) is a medium-energy x-ray telescope system proposed for the Russian-led mission Spectrum Rntgen-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 about 1,000 heavily-obscured (NH > 31023 cm-2) active galactic nuclei (AGN) - in the SRG 4-year all-sky survey, plus a comparable number in deeper wide-field (500 deg2 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 (�-ks) pointed observations, ART can obtain statistically significant spectral data up to about 15 keV 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.

O'Dell, Stephen L.; Ramsey, B. D.; Adams, M. L.; Areviev, V.; Brandt, W. N.; Buntov, M.; Elsner, R. F.; Grigorovich, S.; Gubarev, M. V.; Hasinger, G.; Lapshov, I.; Litvin, D.; Meidinger, N.; Pavlinsky, M.; Predehl, P.; Revnivtsev, M.; Romaine, S. E.; Sazonov, S.; Semena, N.; Swartz, D. A.; Tkachenko, A.; Urry, C. M.; Vikhlinin, A.; Weisskopf, M. C.

2008-03-01

156

MCP image intensifier in the 100-KeV to 1-MeV x-ray range  

NASA Astrophysics Data System (ADS)

A high gain x-ray image intensifier with high sensitivity in the 1 MeV x-ray range is presented and a good spatial resolution developed in order to improve the radiographic detection in the experiments. In particular the gold photocathode and MCP thickness have been optimized to give the best trade-off between the dose sensitivity and the spatial resolution. The large useful 60 mm diameter photocathode set on the MCP input converts the x-ray emission into electrons which are multiplied in the MCP and proximity-focused onto the P11 phosphor screen deposited on a fiber optic plate. For x-ray quanta of 1 MeV energy the x-ray image converter is more sensitive than the most sensitive x-ray screen-film systems. Using, for instance, a pulsed x-ray source the authors were able to record pictures of a sphere or of a testing metallic chart for a dose lower than 100 (mu) rad; under these conditions the spatial resolution was greater than 1 lp/mm and the dynamic range was still around 10. Using an x-ray screen film under the same input level the authors have obtained a very low dynamic range and density values actually equal to the noise level. These unique performances fulfill the requirements of a large number of detonic experiments needing a high sensitivity in the 1 Mev x-ray range.

Veaux, Jacqueline; Cavailler, Claude; Gex, Jean-Pierre; Hauducoeur, Alain; Hivernage, M.

1991-06-01

157

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

SciTech Connect

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.

Li Zhichao; Guo Liang [Department of Modern Physics and CAS Key Laboratory of Basic Plasma Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang, Sichuan 621900 (China); Jiang Xiaohua; Liu Shenye; Huang Tianxuan; Yang Jiamin; Li Sanwei; Zhao Xuefeng; Du Huabin; Song Tianming; Yi Rongqing; Liu Yonggang; Jiang Shaoen; Ding Yongkun [Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang, Sichuan 621900 (China); Zheng Jian [Department of Modern Physics and CAS Key Laboratory of Basic Plasma Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China)

2010-07-15

158

Optical constants for hard x-ray multilayers over the energy range E = 35 - 180 keV  

Microsoft Academic Search

We have determined experimentally optical constants for eight thin film materials that can be used in hard X-ray multilayer coatings. Thin film samples of Ni.97V.03, Mo, W, Pt, C, B4C, Si and SiC were deposited by magnetron sputtering onto superpolished optical flats. Optical constants were determined from fits to reflectance-vs-incidence angle measurements made using synchrotron radiation over the energy range

David L. Windt; Soizik Donguy; Charles J. Hailey; Jason E. Koglin; Veijo Honkimaki; Eric Ziegler; Finn E. Christensen; Fiona A. Harrison

2004-01-01

159

MCP image intensifier in the 100KeV to 1MeV x-ray range  

Microsoft Academic Search

A high gain x-ray image intensifier with high sensitivity in the 1 MeV x-ray range is presented and a good spatial resolution developed in order to improve the radiographic detection in the experiments. In particular the gold photocathode and MCP thickness have been optimized to give the best trade-off between the dose sensitivity and the spatial resolution. The large useful

Jacqueline Veaux; Claude Cavailler; Jean-Pierre Gex; Alain Hauducoeur; M. Hivernage

1991-01-01

160

Measurement of the x-ray mass attenuation coefficients of gold in the 38?50-keV energy range  

SciTech Connect

We used synchrotron x rays to measure the x-ray mass attenuation coefficients of gold at nine energies from 38 to 50 keV with accuracies of 0.1%. Our results are much more accurate than previous measurements in this energy range. A comparison of our measurements with calculated mass attenuation coefficients shows that our measurements fall almost exactly midway between the XCOM and FFAST calculated theoretical values, which differ from one another in this energy region by about 4%, even though the range includes no absorption edge. The consistency and accuracy of these measurements open the way to investigations of the x-ray attenuation in the region of the L absorption edge of gold.

Islam, M.T.; Rae, N.A.; Glover, J.L.; Barnea, Z.; de Jonge, M.D.; Tran, C.Q.; Wang, J.; Chantler, C.T. (Melbourne)

2010-11-12

161

Measurement of the x-ray mass attenuation coefficients of gold in the 38-50-keV energy range  

NASA Astrophysics Data System (ADS)

We used synchrotron x rays to measure the x-ray mass attenuation coefficients of gold at nine energies from 38 to 50 keV with accuracies of 0.1%. Our results are much more accurate than previous measurements in this energy range. A comparison of our measurements with calculated mass attenuation coefficients shows that our measurements fall almost exactly midway between the XCOM and FFAST calculated theoretical values, which differ from one another in this energy region by about 4%, even though the range includes no absorption edge. The consistency and accuracy of these measurements open the way to investigations of the x-ray attenuation in the region of the L absorption edge of gold.

Islam, M. T.; Rae, N. A.; Glover, J. L.; Barnea, Z.; de Jonge, M. D.; Tran, C. Q.; Wang, J.; Chantler, C. T.

2010-02-01

162

Calculation of the total Rayleigh scattering cross sections of photons in the energy range of 30-50 keV for Nb and Mo elements  

NASA Astrophysics Data System (ADS)

The total Rayleigh scattering cross sections are calculated in the energy range of 30-50 keV using the modified relativistic form factors (MRFF), non-relativistic form factors (NFF), and relativistic form factors (RFF). Numerical calculations are made for energies above the K-threshold comparisons, for medium-Z elements (Nb and Mo), primarily at small momentum transfers. The integration range is divided into intervals using a modified formula to take into account the smaller scattering angles. The calculated cross sections based on MRFF, NFF, and RFF are presented and compared with the tabulated theoretical values. It is found that the values calculated using the NFF and RFF are smaller than the tabulated values with a ratio of 3-7%. It is also observed that the smallest total Rayleigh scattering cross section values are obtained using the MRFF.

Bke, Aysun

2011-05-01

163

Web 2.0, Library 2.0, and Librarian 2.0:Preparing for the 2.0 World  

Microsoft Academic Search

There is a global conversation going on right now about the next generation of the web. It's happening under the name of Web 2.0. It's the McLuhanesque hot web where true human interaction takes precedence over merely `cool' information delivery and e-mail. It's about putting information into the real context of our users' lives, research, work and play. Concurrently, a

S. Abram

2007-01-01

164

Study of the 36 Cl( n, p ) 36 S reaction in the neutron energy range up to 10 keV  

Microsoft Academic Search

The36Cl(n,p)36S reaction cross-section was measured by the time-of-flight method in the IBR-30 pulsed reactor of the JINR. The measured cross-section shows three not previously observed neutron resonances with energies En = 1.3; 3.5 and 8.2 keV for which the parameters Ap=gGnGp\\/G: 0.07 0.01; 0.08 + 0.03 and 1.7 + 0.3 eV were determined, respectively. Comparison of these results with the

Yu. M. Gledenov; Yu. P. Popov; J. Rigol; V. I. Salatsky

1985-01-01

165

Study of the36Cl( n, p)36S reaction in the neutron energy range up to 10 keV  

Microsoft Academic Search

The36Cl( n,p)36S reaction cross-section was measured by the time-of-flight method in the IBR-30 pulsed reactor of the JINR. The measured cross-section shows three not previously observed neutron resonances with energies En = 1.3; 3.5 and 8.2 keV for which the parameters Ap= gGammanGammap\\/Gamma: 0.07 0.01; 0.08 + 0.03 and 1.7 + 0.3 eV were determined, respectively. Comparison of these results

Yu. M. Gledenov; Yu. P. Popov; J. Rigol; V. I. Salatsky

1985-01-01

166

Molecular dynamics simulations of 30 and 2 keV Ga in Si  

SciTech Connect

Focused Ga{sup +} ion beams are routinely used at high incident angles for specimen preparation. Molecular dynamics simulations of 2 and 30 keV Ga bombardment of Si(011) at a grazing angle of 88 deg. were conducted to assess sputtering characteristics and damage depth. The bombardment of atomically flat surfaces and surfaces with vacancies shows little energy transfer yielding ion reflection. The bombardment of surfaces with adatoms allows for the coupling of the energy of motion parallel to the surface into the substrate resulting in sputtering. The adatom and one other Si atom eject, and motion in the substrate occurs down to a depth of 13 A. Experimental evidence shows that sputtering is a reality, suggesting that an atomically flat surface is never achieved.

Giannuzzi, Lucille A.; Garrison, Barbara J. [FEI Company, 5350 NE Dawson Creek Drive, Hillsboro, Oregon 97124 (United States); Department of Chemistry, The Pennsylvania State University, 104 Chemistry Building, University Park, Pennsylvania 16802 (United States)

2007-09-15

167

Calibration of X-ray detectors in the 8 to 115 keV energy range and their application to diagnostics on the National Ignition Facility  

SciTech Connect

The calibration of X-ray diagnostics is of paramount importance to the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL). National Security Technologies LLC (NSTec) fills this need by providing a wide variety of calibration and diagnostic development services in support of the ongoing research efforts at NIF. The X-ray source in the High Energy X-ray lab utilizes induced fluorescence in a variety of metal foils to produce a beam of characteristic X rays ranging from 8 to 111 keV. Presented are the methods used for calibrating a High Purity Germanium detector, which has been absolutely calibrated using radioactive check sources, compared against a silicon photodiode calibrated at Physikalisch Technische Bundesanstalt (PTB). Also included is a limited presentation of results from the recent calibration of the upgraded Filter Fluorescer X ray Spectrometer.

J. J. Lee, M. J. Haugh, G. LaCaille, and P. Torres

2012-10-01

168

Mass attenuation coefficients of natural Rhizophora spp. wood for X-rays in the 15.77-25.27 keV range.  

PubMed

The mass attenuation coefficients (mu/rho) of Rhizophora spp. were determined for photons in the energy range of 15.77-25.27 keV. This was carried out by studying the attenuation of X-ray fluorescent photons from zirconium, molybdenum, palladium, silver, indium and tin targets. The results were compared with theoretical values for average breast tissues in young-age, middle-age and old-age groups calculated using photon cross section database (XCOM), the well-known code for calculating attenuation coefficients and interaction cross-sections. The measured mass attenuation coefficients were found to be very close to the calculated XCOM values in breasts of young-age group. PMID:19482883

Shakhreet, B Z; Bauk, S; Tajuddin, A A; Shukri, A

2009-05-29

169

Calibrating of x-ray detectors in the 8 to 111 keV energy range and their application to diagnostics on the National Ignition Facility  

NASA Astrophysics Data System (ADS)

The calibration of X-ray diagnostics is of paramount importance to the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL). National Security Technologies LLC (NSTec) fills this need by providing a wide variety of calibration and diagnostic development services in support of the ongoing research efforts at NIF. The Xray source in the High Energy X-ray lab utilizes induced fluorescence in a variety of metal foils to produce a beam of characteristic X-rays ranging from 8 to 111 keV. Presented are the methods used for calibrating a High Purity Germanium detector, using NIST traceable radioactive sources, and compared against a silicon photodiode calibrated at Physikalisch Technische Bundesanstalt (PTB). A limited presentation of results from the recent calibration of the upgraded Filter Fluorescer X-ray Spectrometer is included.

Lee, Joshua J.; Haugh, Michael J.; LaCaille, Greg; Torres, Peter

2012-10-01

170

Differences in the neutralization of 2. 4--10 keV Ne[sup +] scattered from the Cu and Au atoms of an alloy surface  

Microsoft Academic Search

The neutralization behavior of low-energy Ne[sup +] ions scattered from a compositionally ordered Cu[sub 3]Au(100) surface has been studied over a range of incident energy [ital E][sub 0] from 2.4 to 10 keV. Ion fractions of Ne scattered from Cu atoms in the first, or first two, atom layers exhibited a sharp increase setting in at an [ital E][sub 0

T. M. Buck; W. E. Wallace; R. A. Baragiola; G. H. Wheatley; J. B. Rothman

1993-01-01

171

Range Forage Data Base for 20 Great Plains, Southern, and Western States.  

National Technical Information Service (NTIS)

The paper documents the development and structure of the Range Forage data base, a subset of information from all Soil Conservation Service Range Site Descriptions for 20 states. Information in the data set includes range site name, location identifiers, ...

L. A. Joyce D. E. Chalk A. D. Vigil

1986-01-01

172

Efficiency calibration of a HPGe detector in the [46.54-2000] keV energy range for the measurement of environmental samples  

NASA Astrophysics Data System (ADS)

Here we describe a general method of calibrating the efficiency of a Ge /?-ray spectrometer. The method, which is based on the work of Quintana and Fernndez (Appl. Radiat. Isot. 47 /(1996) 911), can now be applied to many different experimental set-ups including both liquid and solid environmental samples. The method requires two different types of experimental inputs. Firstly, it requires measurements with radioactive sources emitting cascades of /? rays covering the energy range of interest. Secondly, it requires measurements with sources emitting isolated /? rays in order to provide coincidence-summing corrections. On this basis, we establish a general function to describe the energy dependence of the efficiency for the particular geometry and source matrix. The method has been applied to 11 different experimental arrangements to provide efficiency calibrations over the range 46.54-2000keV with associated uncertainties ranging from 0.1% to 1.8%. This allows high precision measurements with environmental samples, which often have very low activities.

Daza, M. J.; Quintana, B.; Garca-Talavera, M.; Fernndez, F.

2001-09-01

173

A NOVEL APPROACH TO MEASURE THE CROSS SECTION OF THE {sup 18}O(p, alpha){sup 15}N RESONANT REACTION IN THE 0-200 keV ENERGY RANGE  

SciTech Connect

The {sup 18}O(p, alpha){sup 15}N reaction is of primary importance to pin down the uncertainties, due to nuclear physics input, affecting present-day models of asymptotic giant branch stars. Its reaction rate can modify both fluorine nucleosynthesis inside such stars and oxygen and nitrogen isotopic ratios, which allow one to constrain the proposed astrophysical scenarios. Thus, an indirect measurement of the low-energy region of the {sup 18}O(p, alpha){sup 15}N reaction has been performed to access, for the first time, the range of relevance for astrophysical application. In particular, a full, high-accuracy spectroscopic study of the 20 and 90 keV resonances has been performed and the strengths deduced to evaluate the reaction rate and the consequences for astrophysics.

La Cognata, M.; Spitaleri, C.; Cherubini, S.; Crucilla, V.; Gulino, M.; Lamia, L.; Pizzone, R. G.; Puglia, S. M. R.; Rapisarda, G. G.; Romano, S.; Sergi, M. L. [INFN - Laboratori Nazionali del Sud and DMFCI - Universita di Catania, Catania (Italy); Mukhamedzhanov, A.; Banu, A.; Goldberg, V.; Tabacaru, G.; Trache, L. [Cyclotron Institute - Texas A and M University, College Station, TX (United States); Coc, A. [CSNSM CNRS/IN2P3, Universite Paris Sud, Orsay (France); Irgaziev, B. [GIK - Institute of Engineering Sciences and Technology, Topi District, Swabi NWFP (Pakistan); Kiss, G. G. [ATOMKI, Debrecen (Hungary); Mrazek, J., E-mail: Spitaleri@lns.infn.i [Nuclear Physics Institute of ASCR, Rez (Czech Republic)

2010-01-01

174

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

PubMed

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. PMID:19887515

Olsher, R H; McLean, T D; Justus, A L; Devine, R T; Gadd, M S

2009-11-03

175

Inverse mean free path, stopping power CSDA range, and straggling in Ni, Cu, and Au for electrons of energy S or equal 10 keV calculated from a statistical model  

Microsoft Academic Search

A statistical model is described and employed to calculate inverse mean free path, stopping power, and mean square energy loss for electrons of energy from 0.5 eV to 10 keV above the Fermi level in several solids. From these calculations, electron range in the continuous-slowing-down approximation and straggling are evaluated for electron energies from 10 eV to 10 keV. Table

J. C. Ashley; C. J. Tung; R. H. Ritchie; V. E. Anderson

1976-01-01

176

Study of the36Cl( n, p)36S reaction in the neutron energy range up to 10 keV  

NASA Astrophysics Data System (ADS)

The36Cl( n,p)36S reaction cross-section was measured by the time-of-flight method in the IBR-30 pulsed reactor of the JINR. The measured cross-section shows three not previously observed neutron resonances with energies En = 1.3; 3.5 and 8.2 keV for which the parameters Ap= g?n?p/?: 0.07 0.01; 0.08 + 0.03 and 1.7 + 0.3 eV were determined, respectively. Comparison of these results with the excited states obtained by the36S( p, ?)37Cl reaction made possible a more exact determination of the scale energy of the37Cl nucleus excited states.

Gledenov, Yu. M.; Popov, Yu. P.; Rigol, J.; Salatsky, V. I.

1985-12-01

177

Stopping power for electrons in pyrimidine in the energy range 20-3000eV.  

PubMed

In this work, we present new experimental electron energy loss distribution functions for pyrimidine (C(4)H(4)N(2)) measured for the incident energy range 30-2000eV. Theoretical total and elastic cross sections for electron scattering from pyrimidine were calculated using the screening-corrected additivity rule (IAM-SCAR) method. Based on the mean energy loss observed in the experiment and the theoretical integral inelastic cross section, the stopping power for electrons in pyrimidine is calculated in the energy range 20-3000eV. PMID:23415108

Colmenares, R; Sanz, A G; Fuss, M C; Blanco, F; Garca, G

2013-01-20

178

Xenon-neon gas proportional-scintillation counters for X rays below 2 keV: experimental results  

Microsoft Academic Search

The energy spectra of X-rays with energies below 2 keV measured with standard Xe filled gas proportional scintillation counters at atmospheric pressure exhibit a distorted tail towards the low energy region, due to the loss of electrons to the detector entrance window. In this framework, a Monte Carlo simulation study taking into account these losses has previously investigated the use

F. I. G. M. Borges; F. P. Santos; J. M. F. dos Santos; T. H. V. T. Dias; P. J. B. M. Rachinhas; C. A. N. Conde

2002-01-01

179

Spectroscopy of Mg20: The isobaric mass multiplet equation for the 2+ states of the A=20, T=2 quintet and distant mirror nuclei  

NASA Astrophysics Data System (ADS)

We report on the first determination of the 21+ energy of Mg20, the most neutron-deficient Mg isotope known to exist. The result, E(21+)=1598(10) keV, obtained from in-beam ?-ray spectroscopy following the two-neutron removal from a Mg22 secondary beam, is discussed in the framework of the isobaric mass multiplet equation (IMME). Resulting predictions for the excitation energies of the T=2,2+ states in the F20 and Na20 isobars are presented. The mirror energy difference, E(21+,Mg20)-E(21+,O20)=-77(10) keV, is compared to a recent prediction within the nuclear shell model based on the USDm - gap Z14< modification of the universal sd (USD) effective interaction.

Gade, A.; Adrich, P.; Bazin, D.; Bowen, M. D.; Brown, B. A.; Campbell, C. M.; Cook, J. M.; Glasmacher, T.; Hosier, K.; McDaniel, S.; McGlinchery, D.; Obertelli, A.; Riley, L. A.; Siwek, K.; Weisshaar, D.

2007-08-01

180

Study of ^2H(d,p)^3H reactions at several ten keV energies by the four-body Faddeev-Yakubovsky equation  

NASA Astrophysics Data System (ADS)

Low energy ^2H(d,p)^3H and ^2H(d,n)^3He reactions are fundamental subjects not only for studies of stellar nucleosynthesis, but also for fusion reactor applications. The differential and integrated cross sections, S-factors, vector and tensor analyzing powers, and some polarization transfer coefficients for the reactions have been measured at incident deuteron energies from several ten to few hundred keV. We analyze these experimental data by solving the four-body Faddeev-Yakubovsky (FY) equation with realistic nuclear interactions and predict the suppression ratio due to polarizations, ?_pol / ?_0, where ?0 is the total cross section for the unpolarized beam and target, and ?_pol is that for the polarized ones. Previously we have reported the FY calculation for the reactions at Ed = 30keV with the PEST potentials, where the data for the differential cross section and the analyzing powers are fairly well reproduced, although with about 20% discrepancies for the cross section magnitude. This time we report the results of the calculations at Ed = 50 - 90 keV.

Uzu, Eizo; Shinsho, Oryu; Makoto, Tanifuji

2001-10-01

181

Thermal expansion of ChS-139 steel in temperature range 20-720 C  

NASA Astrophysics Data System (ADS)

The article presents the results of investigation of thermal expansion of ChS-139 steel in the temperature range 20-720 C. Measurements were carried out by dilatometric method with DIL-402C unit manufactured by NETZSCH (Germany) with the error (1.5-2)10-7 K-1. The approximation dependences of thermal coefficient of linear expansion on temperature have been obtained and reference tables have been calculated. The abnormal change of expansion coefficient above 550 C is shown, and the explanation of the phenomenon is given.

Stankus, S. V.; Kozlovsky, Yu. M.; Yatsuk, O. S.; Verba, O. I.

2013-09-01

182

Using Web 2.0 to Collaborate  

ERIC Educational Resources Information Center

|Web 2.0 is not only for kids anymore, businesses are using it, too. Businesses are adopting Web 2.0 technology for a variety of purposes. In this article, the author discusses how he incorporates Web 2.0 into his business communications course. He describes a project that has both individual and collaborative elements and requires extensive

Buechler, Scott

2010-01-01

183

Energetic (keV) Ionosphere-Origin Ions Found Between R= 2 and 23 R E  

Microsoft Academic Search

With the flight of ion composition instruments on the Polar satellite, beginning some eight years ago, adding to several earlier missions of varied orbits, we now have essentially contiguous altitude records of the outflow of energized ionospheric ions from R= 2 R E (geocentric) to R= 23 R E, at least in the energy range from a few tens of

O. W. Lennartsson

2004-01-01

184

High-resolution integrated germanium Compton polarimeter for the gamma-ray energy range 80 keV1 MeV  

Microsoft Academic Search

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

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

1995-01-01

185

Xenon-neon gas proportional-scintillation counters for X-rays below 2 keV: experimental results  

Microsoft Academic Search

The energy spectra of X-rays with energies below 2 keV measured with standard Xe filled gas proportional-scintillation counters at atmospheric pressure exhibit a distorted tail toward the low energy region, due to the loss of electrons to the detector entrance window. In this framework, a Monte Carlo simulation study taking into account these losses has previously investigated the use of

F. I. G. M. Borges; F. P. Santos; J. M. F. dos Santos; T. H. V. T. Dias; P. J. B. M. Rachinhas; C. A. N. Conde

2003-01-01

186

EQUILIBRIUM MOISTURE CONTENT OF DRIED BLOOD FLOUR FN THE TEMPERATURE RANGE OF 20 - 50C  

Microsoft Academic Search

The paper presents results of water sorption tests of dried blood flour carried out tinder laboratory conditions and mathematical analyses of sorption isotherms obtained. Moisture equilibrium data were investigated at air temperatures in the range of 2050C and water activity ranging from 0 4 to 0 99. The experimental procedure used was a gravimetric dynamic method with continuous registration of

Jiri Stencl Jana Gotlhardova; Pavel Homola

1998-01-01

187

What is Library 2.0?  

Microsoft Academic Search

Purpose The aim of this paper is to define both theoretically and empirically the concept of Library 2.0. Design\\/methodology\\/approach Written answers to the question What is Library 2.0? given by practitioners and researchers (n=29) interested in Library 2.0 issues were analyzed by using co-word analysis to map the underlying elements of the concept. Findings The study resulted

Kim Holmberg; Isto Huvila; Maria Kronqvist-Berg; Gunilla Widn-Wulff

2009-01-01

188

The USC 2.0 Reference Manual  

Microsoft Academic Search

This document is the reference manual for version 2.0 of the Universal Stub Compiler (USC) and the USC Inference Tool (USIT). USC 2.0 is a nearly complete re-implementation with some changes to the syntax of the USC language and the USC and USIT program interface. USC 2.0 is not backwardly compatible with the previous version of USC. USC is a

Sean O'Malley; Todd Proebsting; Gregg Townsend; H. Dan Lambright

189

DISFRAC Version 2.0 Users Guide  

SciTech Connect

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.

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

2013-01-01

190

The g-factor of the 7/2+ 1264.4 KeV level in 97Zr  

NASA Astrophysics Data System (ADS)

The g-factor of the 7/2+ 1264.4 KeV level in 97Zr has been measured using the time-differential perturbed angular correlation method. The resultant g-factor, g=+0.39(4) is consistent with the simple shell model prediction for a ifg7/2 neutron, assuming gs=gsfree. This is in contrastrast to the measured vg7/2g-factors in 115Sn, 121Te, 125,127Xe where consistency is obtained with theoretical calculation by assuming gs~0.7 gsfree and is seen as another confirmation of quasi-shell closure at 96Zr.

Berant, Z.; Gill, R. L.; Rafailovich, M. H.; Chrien, R. E.; Hill, J. C.; Wohn, F. K.; Petry, R. F.; Chung, C.; Peaslee, G.; Mohsen, M.

1985-06-01

191

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

SciTech Connect

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.

Castleton, Karl J.; Meyer, Philip D.

2009-06-17

192

Unique Spectral Features Search In The 20 - 35 Micron Range of Mgs Tes Data  

NASA Astrophysics Data System (ADS)

TES is the Thermal Emission Spectrometer aboard the NASA mission Mars Global Surveyor (MGS) orbiting around Mars since September 1997. It is collecting 6 - 50 micron thermal emission spectra and one of its principal purposes is to determine and map the Mars surface composition. Spectral features directly ascribable to sur- face minerals have been identified in the 20 - 35 micron spectral range: deposits of crystalline gray hematite have been localized in three regions, Sinus Meridiani, Aram Chaos and Valles Marineris [1, 2], and outcrops of olivines have been individuated in Nili Fossae [3]. The crystalline gray hematite areas have been interpreted to be formed by aqueous mineralization, indicating that liquid water was stable near the Mars sur- face for a long period of time in some limited regions. On the other hand there is no evidence in TES data for large scale occurrences (< 10 km) of moderate-grained (> 50 micron) carbonates exposed at the surface at a detection limit of 10 % [2]. Mars thermal emission spectra show, in general, significant variance between 20 and 35 mi- cron. This variance is not directly attributable to surface mineralogical components for the difficulty of discriminating the contribute of atmospheric components: CO2 and water vapour gas, dust and water ice aerosols. Moreover, the dust layer deposited on the soil has a spectral masking effect, obscuring superficial signature related to smaller mineral deposit and making difficult their identification. In this study we report some examples of single TES spectra with typical hematite and olivine bands and spectra with other unique features in the 20 - 35 micron range likely related to superficial components. For some of them we have analysed how the spectral features change in two different Mars seasons. These single TES pixels could be best investigated by instruments with an higher spatial resolution, as THEMIS and OMEGA. References: [1] Christensen P. R., et al., JGR, 105, 9623-9642, 2000. [2] Christensen P. R., et al., JGR,106, 23823-23871, 2001. [3] Hoefen T. M. and Clark R. N., LPS XXXII, 2049, 2001.

Altieri, F.; Bellucci, G.

193

THE RGI-20 RADIAC SYSTEMA WIDE RANGE BETA-GAMMA INSTRUMENT. II. THE SOLID STATE PULSED GM TUBE LOW RANGE ACCESSORY PROBE  

Microsoft Academic Search

A plug-on low-range accessory, consisting of a main unit and a cable-; connected probe, was developed for the RGI-20 radiac system. The solid-state ; circuit for pulsed GM tube operation is contained in the main unit whose ; dimensions are approximately 2 x 2 1\\/2 x 8 in. The GM tube is mounted in a cable-; connected probe with side

1963-01-01

194

Young Adult Literature 2.0  

ERIC Educational Resources Information Center

|Web 2.0 tools enable today's writers to connect with their audience in unprecedented ways. The advent of social networking and other Web 2.0 tools have changed the rules for how authors and book publishers market and communicate with their audience. Through tools like blogs, Twitter, MySpace, and Facebook, Young Adult (YA) lit authors can choose

Hamilton, Buffy

2009-01-01

195

Student Inquiry and Web 2.0  

ERIC Educational Resources Information Center

|Web 2.0 applications are changing how educators interact both with each other and with their students. Educators can use these new Web tools daily to create, share, socialize, and collaborate with students, colleagues, and newly developed network contacts. School librarians are finding that Web 2.0 tools are bringing them more ways to embrace and

Berger, Pam

2010-01-01

196

Web 2.0: hype or happiness?  

Microsoft Academic Search

Web 2.0 has initiated a new age of Web interaction. Countless everyday activities such as seeking information, shopping, filling in forms and making appointments can be done effectively and often more cheaply on the Web. However many of the new community sites, and other Web 2.0 sites, do not promote accessibility in terms of inclusivity. They are built for, and

Mary Zajicek

2007-01-01

197

Web 2.0 Creates Security Challenges  

Microsoft Academic Search

By its very nature, Web 2.0 is interactive, allowing users to add input such as participatory book reviews, blogs, wikis, social net works, and video- and photo sharing services to Web sites. Web 2.0 has consequently become very popular with users and Web site operators. However, the approach's interactivity has also made it popular with hackers. This paper discusses some

George Lawton

2007-01-01

198

Trust, Voice, and Library 2.0  

ERIC Educational Resources Information Center

|Web 2.0 is a constant and growing theme in the library field. This article describes a social networking site based on a Web 2.0 infused course management system (CMS) developed by Clatsop Community College in Astoria, Oregon.|

Watkins, Candice

2009-01-01

199

A multilayer grating with a novel layer structure for a flat-field spectrograph attached to transmission electron microscopes in energy region of 2-4 keV  

NASA Astrophysics Data System (ADS)

A multilayer mirror with a novel layer structure to uniformly enhance the reflectivity in a few keV energy range at a fixed angle of incidence is invented and applied to a multilayer grating for use in a flat-field spectrograph attached to a conventional electron microscope. The diffraction efficiency of the fabricated multilayer grating having the new layer structure is evaluated at the angle of incidence of 88.65 in the energy region of 2.1-4.0 keV. It is shown that the multilayer grating is effective to uniformly enhance the diffraction efficiency and able to be practically used in this energy region.

Imazono, T.; Koike, M.; Koeda, M.; Nagano, T.; Sasai, H.; Oue, Y.; Yonezawa, Z.; Kuramoto, S.; Terauchi, M.; Takahashi, H.; Handa, N.; Murano, T.

2012-05-01

200

A multilayer grating with a novel layer structure for a flat-field spectrograph attached to transmission electron microscopes in energy region of 2-4 keV  

SciTech Connect

A multilayer mirror with a novel layer structure to uniformly enhance the reflectivity in a few keV energy range at a fixed angle of incidence is invented and applied to a multilayer grating for use in a flat-field spectrograph attached to a conventional electron microscope. The diffraction efficiency of the fabricated multilayer grating having the new layer structure is evaluated at the angle of incidence of 88.65 deg. in the energy region of 2.1-4.0 keV. It is shown that the multilayer grating is effective to uniformly enhance the diffraction efficiency and able to be practically used in this energy region.

Imazono, T.; Koike, M.; Koeda, M.; Nagano, T.; Sasai, H.; Oue, Y.; Yonezawa, Z.; Kuramoto, S.; Terauchi, M.; Takahashi, H.; Handa, N.; Murano, T. [QuBS, Japan Atomic Energy Agency (JAEA), 8-1-7 Umemidai, Kizugawa, Kyoto 619-0215 (Japan); Device Dept., Shimadzu Corp., 1 Nishinokyo-Kuwabarcho, Nakagyo-ku, Kyoto 604-8511 (Japan); IMRAM, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); EC Business Unit, JEOL Ltd., 3-1-2 Musashino, Akishima, Tokyo 196-8558 (Japan)

2012-05-17

201

DECAYS OF THE Tz = -2 NUCLEI 20Mg, 24Si AND 36Ca  

SciTech Connect

Beta-delayed protons have been observed from the decays of the mass separated T{sub z} = -2 nuclides {sup 20}Mg, {sup 24}Si, and {sup 36}Ca. From these proton spectra the mass excesses of the lowest T = 2 states in the T{sub z} = -1 nuclei {sup 20}Na, {sup 24}Al, and {sup 36}K are determined to be 13420 {+-} 50 keV ({sup 20}Na), 5903 {+-} 9 keV ({sup 24}Al), and - 13168 {+-} 22 keV ({sup 36}K). The complete A = 20, 24, and 36 isospin quintets have all their members bound against isospin allowed particle-decay modes, providing a stringent test of the isobaric multiplet mass equation. Good agreement is observed for all these quintets using only the quadratic form of this equation. Radioactivity {sup 20}Mg, {sup 24}Si, {sup 36}Ca (mass separated); measured {beta}-delayed protons; deduced T{sub 1/2} and proton branching; derived mass excesses of the lowest 0{sup +}, T = 2 states in {sup 20}Na, {sup 24}Al, and {sup 36}K; deduced coefficients of the isobaric multiplet mass equation.

Aysto, J.; Cable, M.D.; Parry, R.F.; Wouters, J.M.; Moltz, D.M.; Cerny, J.

1980-06-01

202

Do the O2 Schumann-Runge Bands Participate in keV Collision-Induced Dissociation Experiments?  

NASA Astrophysics Data System (ADS)

In high-energy (keV) CID experiments, oxygen has the unique ability to enhance specific ion fragmentation pathways that lie within a relatively narrow band of activation energy. It has been previously proposed that this oxygen-enhanced dissociation phenomenon is due to the participation of the {{O}_{{2}}}{B}{ ^{{3}}}{?_{{u}}}^{ + } - {X}{ ^{{3}}}{?_{{g}}}^{ - } (Schumann-Runge) system in the collision complex. During the collision, oxygen is first excited to its {B}{ ^{{3}}}{?_{{u}}}^{ + } state before it returns this energy to the projectile ion. This energy drives the nonstatistical dissociation of the projectile provided there is an energetically accessible pathway in resonance with the absorbed radiation. To probe the validity of this hypothesis, a modified VG-ZAB mass spectrometer was used to observe the photon emissions from keV collisions of a selection of projectile ions with O2 target gas. By studying the resulting collision-induced emission (CIE) spectra, a second potential mechanism came to light, one that involves the near-isoenergetic O2 +. A 2?u?X 2 ?g state transition.

Lin, Yawei; Mayer, Paul M.

2011-01-01

203

Fully Differential and Double Differential Cross Sections for Single Ionization of H2 by 75 keV Proton Impact  

NASA Astrophysics Data System (ADS)

We have calculated 3DW-EIS (3 body distorted wave -- Eikonal initial state) fully differential cross sections (FDCS) and doubly differential cross sections (DDCS) for single ionization of H2 by 75 KeV proton impact. Previously published DDCS (differential in the projectile scattering angle and integrated over the ejected electron angles) have found pronounced structures at relatively large angles which were interpreted as an interference resulting from the two-center potential of the molecule. We will investigate the source of these interference effects in the FDCS and examine how interference at the fully differential level can be still observable at the double differential level.

Chowdhury, Uttam; Schulz, Michael; Madison, Don

2009-10-01

204

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

NASA Astrophysics Data System (ADS)

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.

Gowda, Shivalinge; Krishnaveni, S.; Gowda, Ramakrishna

2005-10-01

205

Differential elastic scattering cross sections of 22.1-keV x rays by elements in the range 22<=Z<=82  

NASA Astrophysics Data System (ADS)

Elastic scattering cross sections of 22.1-keV x rays by the elements Ti, V, Fe, Ni, Cu, Zn, Zr, Nb, Mo, Pd, Cd, In, Sn, Sm, Gd, Dy, Er, Yb, Au, and Pb have been measured at 90 with an overall error of 8-10 %. The 22.1-keV x rays were obtained from a Ag foil used as a secondary target in an x-ray fluorescence setup. Experimental cross sections have been compared with the nonrelativistic form factors (NFF), relativistic form factors, modified relativistic form factor (MRFF), relativistic form factor with anomalous scattering correction (RFFASF), modified relativistic form factor with anomalous scattering correction (MRFFASF), and the S matrix calculations. For low Z elements, experimental values are better represented by S matrix, RFFASF, and MRFFASF. For the elements Nb, Mo, and Pd whose K shell binding energies are very close to the exciting energy, the data are higher than all of the theoretical predictions. For higher Z elements, NFF and MRFF give a better agreement with the present data.

Mandal, A. C.; Mitra, D.; Sarkar, M.; Bhattacharya, D.

2002-10-01

206

Ion-atom scattering and interatomic potentials for ions of noble metals and period II elements incident on neon and argon with energies in the range 8-25 keV  

Microsoft Academic Search

Information about the potential energy of interaction was obtained for the metal ions, Na+, Mg+, Al+, P+, Cl+, Cu+, Ag+, Au+, Ni+, Zr+, on the inert gases Ar0, Ne0. The scattering of an ion beam in the energy range 8-25 keV, by passage through a gas, was used to measure incomplete total cross sections against energy curves from which the

C. Foster; I. H. Wilson; M. W. Thompson

1972-01-01

207

Efficient production of 100 keV deuterons in deuterium gas puff Z-pinches at 2 MA current  

NASA Astrophysics Data System (ADS)

Deuterium gas puff experiments were carried out on the S-300 Z-pinch at the Kurchatov Institute in Moscow. Gas puffs imploded onto the axis before a current peak at about 100 ns. Fusion neutrons were generated after the gas puff implosion during global expansion of a plasma column. Neutron emission lasted on average 35 5 ns (full width half maximum, FWHM). In the downstream direction (on the Z-pinch axis behind the cathode), a mean neutron energy was 2.6 0.1 MeV. Side-on neutron energy spectra peaked at 2.40 0.05 MeV with about 600 150 keV FWHM. A broad width of side-on neutron spectra implied a high radial component of deuteron velocities. An average kinetic energy of fast deuterons, which produced fusion neutrons, was 150 keV. A peak neutron yield reached a value of 6 1010 on a current level of 1.5 MA. It was by one order higher in comparison with other deuterated loads used on the same current generator. On the basis of experimental observations, we concluded that a total energy of deuterons accelerated to fusion energies was above 1.5 kJ. It is more than 15% of the energy input into a plasma. Therefore gas puff Z-pinches seem to be not only powerful sources of x-ray radiation but also efficient sources of 100 keV deuterons. Such a result is consistent with high neutron yields observed on the Angara Z-pinch and plasma foci with similar currents.

Klir, D.; Kravarik, J.; Kubes, P.; Rezac, K.; Cikhardt, J.; Litseva, E.; Hyhlik, T.; Ananev, S. S.; Bakshaev, Yu L.; Bryzgunov, V. A.; Chernenko, A. S.; Kalinin, Yu G.; Kazakov, E. D.; Korolev, V. D.; Ustroev, G. I.; Zelenin, A. A.; Juha, L.; Krasa, J.; Velyhan, A.; Vysin, L.; Sonsky, J.; Volobuev, I. V.

2010-06-01

208

Transmission images and evaluation of tomographic imaging based scattered radiation from biological materials using 10, 15, 20 and 25 keV synchrotron X-rays: An analysis in terms of optimum energy  

Microsoft Academic Search

Transmission images and tomographic imaging based scattered radiation is evaluated from biological materials, for example, Polyethylene, Poly carbonate, Plexiglas and Nylon using 10, 15, 20 and 25 keV synchrotron X-rays. The SYRMEP facility at Elettra,Trieste, Italy and the associated detection system has been used for the image acquisition. The scattered radiation is detected for each sample at three energies at

Donepudi V. Rao; Takao Akatsuka; Giuliana Tromba

2004-01-01

209

Carbon Capture (Carbon Cycle 2.0)  

SciTech Connect

Berend Smit speaks at the Carbon Cycle 2.0 kick-off symposium Feb. 3, 2010. We emit more carbon into the atmosphere than natural processes are able to remove - an imbalance with negative consequences. Carbon Cycle 2.0 is a Berkeley Lab initiative to provide the science needed to restore this balance by integrating the Labs diverse research activities and delivering creative solutions toward a carbon-neutral energy future. http://carboncycle2.lbl.gov/

Smit, Berend

2010-02-03

210

WATER VAPOR s-t DIAGRAM FOR TEMPERATURE RANGE FROM -20 TO +40 C  

Microsoft Academic Search

The paper presents formulas and algorithm for composition of water vapor s-t-diagram for temperature (t) range from -20 to +40 C. The algorithm may be used by everybody interested in analyzing humid air thermodynamical properties at low and moderate temperatures and energy transformations connected with transition of water vapor. A spreadsheet that is capable of creating output data in the

Valfrid Treier; Veli Palge

211

A simple viscoelastic model for soft tissues the frequency range 6-20 MHz  

Microsoft Academic Search

In this paper, we present measurements of the shear properties of porcine skeletal muscle, liver, and kidney and a novel model describing them. Following a previously used method, shear mechanical impedances are measured, and complex shear moduli are obtained in the frequency range 6-20 MHz. As indicated in previous results, negative storage moduli are obtained in some measurements, which yield

Xinmai Yang; Charles C. Church

2006-01-01

212

Web 2.0 and You!  

NSDL National Science Digital Library

Web 2.0 tools, when used in concert with solid constructivist teaching principles, have the potential to engage digital learners in their own education. These tools are more than resources; they are vital elements in meaningful instruction.

Dyck, Brenda A.

2010-08-01

213

Definition of Health 2.0 and Medicine 2.0: A Systematic Review  

PubMed Central

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 of Health 2.0/Medicine 2.0 and recurrent topics within the definitions. Methods A systematic literature review of electronic databases (PubMed, Scopus, CINAHL) and gray literature on the Internet using the search engines Google, Bing, and Yahoo was performed to find unique definitions of Health 2.0/Medicine 2.0. We assessed all literature, extracted unique definitions, and selected recurrent topics by using the constant comparison method. Results We found a total of 1937 articles, 533 in scientific databases and 1404 in the gray literature. We selected 46 unique definitions for further analysis and identified 7 main topics. Conclusions Health 2.0/Medicine 2.0 are still developing areas. Many articles concerning this subject were found, primarily on the Internet. However, there is still no general consensus regarding the definition of Health 2.0/Medicine 2.0. We hope that this study will contribute to building the concept of Health 2.0/Medicine 2.0 and facilitate discussion and further research.

Engelen, Lucien JLPG; Berben, Sivera AA; Schoonhoven, Lisette

2010-01-01

214

Measurement of the thermal conductivities of 2-amino-2-methyl-1,3-propanediol (AMP), 2-amino-2-hydroxymethyl-1,3-propanediol (TRIS) and the mixture (AMP+TRIS, mole ratio 50:50) in the temperature range from 20C to their supermelting temperatures  

Microsoft Academic Search

2-Amino-2-methyl-1,3-propanediol (AMP), 2-amino-2-hydroxymethyl-1,3-propanediol (TRIS) and the mixture (AMP+TRIS, mole ratio 50:50) are being considered as potential candidates for the thermal storage of energy. The thermal conductivities have been measured with an uncertainty of 3% from 20C to the supermelting points of these substances by means of a calorimeter equipped with a thermistor. The experimental thermal conductivities of the substances under

Zhi-Ying Zhang; Yu-Peng Xu

2001-01-01

215

Web 2.0: Building Enterprise Portals  

Microsoft Academic Search

Various types of Web resources are being made available programmatically using APIs and through data feeds, facilitating the development of highly interactive applications with rich media content - the so called Web 2.0 applications. Most current Web 2.0 applications are simple mashups that combine information from multiple sources and provide a Windows-like user interface. More sophisticated Web programming techniques based

George Feuerlicht; Shyam Govardhan

2008-01-01

216

Lost in Web 2.0 Cyberspace?  

ERIC Educational Resources Information Center

|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

Fallon, Julia

2008-01-01

217

Combustion and Carbon Cycle 2.0 and Computation in CC 2.0 (Carbon Cycle 2.0)  

SciTech Connect

Robert Cheng and Juan Meza provide two presentations in one session at the Carbon Cycle 2.0 kick-off symposium Feb. 3, 2010. We emit more carbon into the atmosphere than natural processes are able to remove - an imbalance with negative consequences. Carbon Cycle 2.0 is a Berkeley Lab initiative to provide the science needed to restore this balance by integrating the Labs diverse research activities and delivering creative solutions toward a carbon-neutral energy future. http://carboncycle2.lbl.gov/

Cheng, Robert K.; Meza, Juan

2010-02-03

218

Analysis of photon emission from 50--350-keV proton impact on H{sub 2}O  

SciTech Connect

We have measured photon emission cross sections from neutral fragments produced by collisions of 50-350 keV protons with H{sub 2}O molecules. Balmer {alpha}-{delta} emissions from both the target and projectile were recorded. We also analyzed A {sup 2}{Sigma}{sup +}-X {sup 2}{Pi} (0,0) and (1,0) emission from the excited OH fragment produced during target dissociation. Trends in the cross sections revealed two key properties of the collision process: (1) The Bethe theory accurately describes target emission from both H and OH fragments and (2) the ratio of any two Balmer emission cross sections for both the target and projectile can be approximated by simple functions of the respective optical oscillator strengths. Finally, we provide the Bethe fit parameters necessary to calculate the target emission cross sections at all nonrelativistic impact energies.

Goldman, Benjamin D.; Timpone, Stephanie A.; Monce, Michael N.; Mitchell, Laurel; Griffin, Brian [Daghlian Accelerator Laboratory, Department of Physics, Astronomy, and Geophysics, Connecticut College, New London, Connecticut 06320 (United States)

2011-04-15

219

Accurate electron inelastic cross sections and stopping powers for liquid water over the 0.1-10 keV range based on an improved dielectric description of the Bethe surface.  

PubMed

Electron inelastic cross sections and stopping powers for liquid water over the 0.1-10 keV range are presented based on a recently developed dielectric response model for liquid water (D. Emfietzoglou, F. Cucinotta and H. Nikjoo, Radiat. Res. 164, 202-211, 2005) that is consistent with the experimental data over the whole energy-momentum plane. Both exchange and second-order Born corrections are included in a material-specific way using the dielectric functions of liquid water. The numerical results are fitted by simple analytic functions to facilitate their further use. Compared to previous studies, differential cross sections are shifted toward smaller energy losses resulting in smaller inelastic and stopping cross sections with differences reaching, on average, the approximately 20% and approximately 50% level, respectively. Contrary to higher energies, it is shown that the dispersion model for the momentum dependence of the dielectric functions (Bethe ridge) is as important as the optical model used. Within the accuracy of the experimental data (a few percent) upon which our dielectric model is based, the calculations are "exact" to first order, while the uncertainty of the results beyond first order is estimated at the 5-10% level. The present work overcomes the limitations of Bethe's theory at low energies by a self-consistent account of inner-shell effects and may serve to extend the ICRU electron stopping power database for liquid water down to 100 eV with a level of uncertainty similar to that for the higher-energy values. PMID:17214512

Emfietzoglou, D; Nikjoo, H

2007-01-01

220

The response of a radiation resistant ceramic scintillator (Al{sub 2}O{sub 3}:Cr) to low energy ions (0-60 keV)  

SciTech Connect

This work extends a previous study on ionoluminescence of a radiation-hard ceramic scintillator, Al{sub 2}O{sub 3}:Cr, to ions accelerated to keV energies [K. J. McCarthy et al., J. Nucl. Mater. 321, 78 (2003)]. It is motivated by the identification of this material as a promising candidate for use in the fast-ion-loss detector for ITER [for the range of thermal (low energy) and suprathermal ions]. In the paper we quantify and compare its ionoluminescence with that of some common luminescent materials (YAG:Ce and ruby) when irradiated by H{sup +} ions accelerated to {<=}60 keV using a purpose built laboratory setup. Next, studies are made on the ceramic to quantify its response as a function of incident ion mass, i.e., to He{sup +}. For this, the absolute luminosities of the material are estimated in terms of the number of photons emitted per incident ion as a function of energy. Moreover, the radiation hardness and postirradiation recovery of the ceramic are investigated. Finally, from the studies it can be concluded that the ceramic ruby is a good candidate for detecting low energy ions as long as its temporal response (approximately several milliseconds) is not a constraint for specific ion measurements.

Jimenez-Rey, D.; Zurro, B.; McCarthy, K. J.; Baciero, A. [Laboratorio Nacional de Fusion por Confinamiento Magnetico, Asociacion Euratom-CIEMAT, Av. Complutense 22, E-28040, Madrid (Spain); Garcia, G. [Instituto de Matematicas y Fisica Fundamental, Consejo Superior de Investigaciones Cientificas, Serrano 113-bis, 20806, Madrid (Spain)

2008-10-15

221

Metamagnetic Behavior in Heavy Fermion Compounds UCo2Zn20 and UIr2Zn20  

NASA Astrophysics Data System (ADS)

The metamagnetic behavior, which is typical in heavy fermion compounds, is observed in UCo2Zn20 and UIr2Zn20 at Hm = 80 and 20 kOe, respectively. Reflecting the metamagnetic behavior, the magnetoresistance is suppressed in magnetic fields larger than Hm, and the corresponding A-value of a Fermi liquid relation in the electrical resistivity ? = ?0+AT2 indicates a peak at around Hm. Pressure suppresses this behavior in UIr2Zn20.

Hirose, Y.; Enoki, K.; Yoshiuchi, S.; Takeuchi, T.; Honda, F.; Sugiyama, K.; Yamamoto, E.; Haga, Y.; Hagiwara, M.; Kindo, K.; Settai, R.; ?nuki, Y.

2012-12-01

222

PROPERTIES OF PHANTOM TISSUE-LIKE POLYMETHYLPENTENE IN THE FREQUENCY RANGE 20-70 MHZ  

PubMed Central

Quantitative ultrasound (QUS) has been employed to characterize soft tissues at ordinary abdominal ultrasound frequencies (215 MHz) and is beginning application at high frequencies (2070 MHz). For example, backscatter and attenuation coefficients can be estimated in vivo using a reference phantom. At high frequencies it is crucial that reverberations do not compromise the measurements. Such reverberations can occur between the phantom's scanning window and transducer components as well as within the scanning window between its surfaces. Transducers are designed to minimize reverberations between the transducer and soft tissue. Thus, the acoustic impedance of a phantom scanning window should be tissue-like; polymethylpentene (TPX) is commonly used because of its tissue-like acoustic impedance. For QUS it is also crucial to correct for the transmission coefficient of the scanning window. Computation of the latter requires knowledge of the ultrasonic properties, viz, density, speed and attenuation coefficients. This work reports values for the ultrasonic properties of two versions of TPX over the high frequency range. One form (TPX film) is used as a scanning window on high frequency phantoms, and at 40 MHz and 22C was found to have an attenuation coefficient of 120 dB/cm and a propagation speed of 2093 m/s.

Madsen, Ernest L; Deaner, Meagan E; Mehi, James

2011-01-01

223

Microstructure and biocompatibility investigation of biomaterial alumina after 30keV and 60keV nitrogen ion implantation  

Microsoft Academic Search

Polycrystalline alumina is widely used as biomaterial. It is being used as hip joints, tooth roots etc. Commercially available polycrystalline alumina samples were implanted with 30keV and 60keV energy N+ ions at different ion doses ranging from 51015ions\\/cm2 to 51017ions\\/cm2. Change in surface structure is studied using optical microscope. Compound formation at the surface of alumina is confirmed with GXRD.

Deep Shikha; Usha Jha; S. K. Sinha; P. K. Barhai; K. G. M. Nair; S. Dash; A. K. Tyagi; S. Kalavathy; D. C. Kothari

2009-01-01

224

Lowest 2+, T=2 states in 20Mg and 20F  

NASA Astrophysics Data System (ADS)

A recent experiment located the lowest 2+ state in 20Mg and discovered that the corresponding 2+, T = 2 state in 20F does not fit expectations of the isobaric multiplet mass equation without a d term. We have calculated the energies of the ground and 2+ states in 20Mg and the 2+ in 20F in a potential model, using shell-model spectroscopic factors. We conclude that this important 20F state has likely never been observed, and suggest a reaction to find it.

Fortune, H. T.; Sherr, R.; Brown, B. A.

2012-05-01

225

Differential cross sections for single ionization of H{sub 2} by 75-keV proton impact  

SciTech Connect

We have calculated triply differential cross sections (TDCS) and doubly differential cross sections (DDCS) for single ionization of H{sub 2} by 75-keV proton impact using the molecular three-body distorted-wave-eikonal initial-state (M3DW-EIS) approach. Previously published measured DDCS (differential in the projectile scattering angle and integrated over the ejected electron angles) found pronounced structures at relatively large angles that were interpreted as an interference resulting from the two-centered potential of the molecule. Theory treating H{sub 2} as atomic H multiplied by a molecular interference factor only predicts the observed structure when assumptions are made about the molecular orientation. Here we apply the M3DW-EIS method, which does not rely on such an ad hoc approach, but rather treats the interference from first principles.

Chowdhury, U.; Schulz, M.; Madison, D. H. [Missouri University of Science and Technology, Department of Physics and Laboratory for Atomic, Molecular, and Optical Research, Rolla, Missouri 65401 (United States)

2011-03-15

226

Coherence Study of 2PSIGMA-2P pi Rotational Coupling: Li(2 exp 2 P) and He(2 exp 1 P) Orientation and Alignment in 1-25 KeV Li exp + -He Collisions.  

National Technical Information Service (NTIS)

We have studied the alignment and orientation of the electron cloud of the Li(2 exp 2 P) and He(2 exp 1 P) states excited by 2psigma-2p pi rotational coupling for impact parameters between 0.2 and 1.1 a.u. in 1-25 keV Li exp + -He collisions by coherence ...

N. Andersen T. Andersen H. P. Neitzke E. Horsdal Pedersen

1984-01-01

227

World Wide Web Astronomy 2.0  

NASA Astrophysics Data System (ADS)

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

Koppelman, M.; Gay, P. L.

2008-11-01

228

Improved measurements of noise and resolution of x-ray framing cameras at 1-2 keV  

NASA Astrophysics Data System (ADS)

We describe x-ray framing cameras that were developed for experiments on the Nike laser system at the Naval Research Laboratory. These cameras have internal impedance matching to allow use of 50? pulsing systems from 100 ps to several nanoseconds, or for long pulse/dc operation. The cameras have been optimized for spatial resolution and low light scatter using aluminized phosphors. One of these cameras has been coupled to a charge coupled device camera and the total system was tested for resolution and image noise using both electrons and x rays. The spatial resolution was found to be well fitted to a Gaussian modulation transfer function with a value of 0.5 at 10 lp/mm. A detailed analysis of the noise in the images was performed for electrons and x rays. The noise in the images is determined by a detective quantum efficiency of approximately 10% for 1-2 keV x-ray photons.

Pawley, Carl J.; Deniz, A. V.

2000-03-01

229

Optical functions of layered cadmium dichalcogenide crystals in the energy range 420 eV  

Microsoft Academic Search

In this work we present the calculations of the optical functions of CdBr2 (space group D~d) and CdI2 (space group C~v) crystals in the energy range 3-20 eV at T = 77~ On their basis and using also the calculations from first principles by the pseudopotential method in the nonlocal approximation [5], quantitative band schemes for the indicated crystals are

Ya. O. Dovgii; I. V. Kityk; Yu. M. Aleksandrov; V. N. Kolobanov; V. N. Makhov; V. V. Mikhailin

1985-01-01

230

Relative partial ionization cross sections of N2O under 10-25-keV electron impact  

NASA Astrophysics Data System (ADS)

The relative partial ionization cross sections for the fragment ions produced in direct and dissociative ionization of a N2O molecule are measured for impact of 10-25-keV electrons by using an electron-ion-coincidence technique with a linear time-of-flight spectrometer. The six ionic fragments of N2O (N2O+, NO+, N2+, O+, N+, and N2+ + O2+) are observed and identified. The impact energy dependence of the partial ionization cross sections for these ions is expressed relative to the cross section of N2O+ and is found to be nearly invariant. The relative ionic fractions for the produced ions of N2O are also obtained and compared with the earlier reported data available at lower energies of electron impact. It is found that the relative ionic fractions for singly charged fragments are almost energy independent. However, for the doubly charged fragment ions (N2+ + O2+), the present data are found to be higher by almost a factor of four compared to the relative ionic fraction reported earlier at a very low impact energy.

Bhatt, Pragya; Singh, Raj; Yadav, Namita; Shanker, R.

2012-03-01

231

3-10 KeV and 0.1- to 2-MeV Observations of Four gamma-Ray Bursts.  

National Technical Information Service (NTIS)

Four catalogued gamma -ray bursts that occurred between 79/3/7 and 79/7/31 have been observed over the 3 to 10 keV range by a joint NRL/Los Alamos experiment on the Air Force P78-1 satellite. The bursts were also well observed by members of the interplane...

J. G. Laros W. D. Evans E. E. Fenimore R. W. Klebesadel S. Shulman

1983-01-01

232

The low energy particle detector sled (~30 keV3.2 MeV) and its performance on the phobos mission to mars and its moons  

Microsoft Academic Search

A low energy particle detector system (SLED) is described which was designed to measure the flux densities of electrons and ions in the energy range from ~30 keV to a few MeV in (a) the varying solar aspect angles and temperatures pertaining during the Cruise Phase of the Phobos Mission and (b) in the low temperature environment (reaching -25 C)

S. McKenna-Lawlor; V. V. Afonin; K. I. Gringauz; E. Keppler; E. Kirsch; A. Richter; M. Witte; D. O'Sullivan; A. Thompson; A. J. Somogyi; L. Szabo; A. Varga

1990-01-01

233

36 CFR 20.2 - Permits; conditions.  

Code of Federal Regulations, 2013 CFR

...ISLE ROYALE NATIONAL PARK; COMMERCIAL FISHING § 20.2 Permits; conditions. ...facilities in the Park as bases for commercial fishing in the waters contiguous to the Park...reside at their Park bases during the fishing season. (c) Permittees shall...

2013-07-01

234

Web 2.0 use by librarians  

Microsoft Academic Search

The current research explores whether librarians, whose main work focuses on information, are familiar with new technological changes and innovations, and whether they make use of different Web 2.0 applications. The research examines whether personality characteristics (resistance to change, cognitive appraisal, empowerment and extroversion or introversion), as well as computer expertise, motivation, importance and capacity towards studying and integrating different

Noa Aharony

2009-01-01

235

Norwegian Parties and Web 2.0  

Microsoft Academic Search

The focus of this article is on Norwegian political parties' adaption of Web 2.0 before and during the long campaign for the local elections in September 2007. By 2007, most parties had learned to use their Web sites as instruments for professional political marketing. In this process of streamlining, party presence on the Web acquired the characteristics of what is

yvind Kalnes

2009-01-01

236

Educational Uses of Web 2.0  

NSDL National Science Digital Library

Educational Uses of Web 2.0 is a presentation that was delivered at the SAME-TEC advanced technological education conference on July 30, 2008 by Mike Qaissaunee and Gordon Synder of NCTT. This presentation covers: blogs, cellphones, webware, mindmapping, video-online meetings, information gathering, ultra-aggregators, bookmarks.

Qaissaunee, Michael; Synder, Gordon

2010-04-14

237

Professional Development and Web 2.0  

ERIC Educational Resources Information Center

|Professional development in most schools has a predictable look and feel: summer workshops, brown-bag luncheon trainings, and the infamous in-service day. These events can be successful, and there is no doubt they have helped numerous educators become better at what they do. Web 2.0, however, opens up a new world of professional learning. This

Jakes, David

2007-01-01

238

Change Management Meets Web 2.0  

ERIC Educational Resources Information Center

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

Gale, Doug

2008-01-01

239

BioSense 2.0  

PubMed Central

Objective To familiarize public health practitioners with the BioSense 2.0 application and its use in all hazard surveillance. Introduction BioSense 2.0 protects the health of the American people by providing timely insight into the health of communities, regions, and the nation by offering a variety of features to improve data collection, standardization, storage, analysis, and collaboration. BioSense 2.0 is the result of a partnership between the Centers for Disease Control and Prevention (CDC) and the public health community to track the health and well-being of communities across the country. In 2010, the BioSense Program began a redesign effort to improve features such as centralized data mining and addressing concerns that the system could not meet its original objective to provide early warning or detect local outbreaks. Methods Using the latest technology, BioSense 2.0 integrates current health data shared by health departments from a variety of sources to provide insight on the health of communities and the country. By getting more information faster, local, state, and federal public health partners can detect and respond to more outbreaks and health events more quickly. From flu outbreaks to car accidents, BioSense 2.0 provides the critical data, information, and tools that public health officials need to better understand and address health problems at the local, state, regional, and national levels. Also, by knowing what is happening across local borders, public health professionals can anticipate potential health problems and respond effectively to protect the health of all people. The demonstration will include a basic overview of the BioSense 2.0 application and the functionality available to public health departments and their data providers. The presenter will also show an example of how BioSense 2.0 can be used in a real-world public health example. Conclusions Over the past two years much has been accomplished during the redesign effort. BioSense 2.0 was launched in November of 2011 and the collaboration between the BioSense program and the public health community has yielded an application based on a user-centered design approach and built on a platform that allows for flexible data sharing across jurisdictions and with partners. The public health community has played a critical role in designing and improving the BioSense 2.0 application and through continued collaboration the system will continue to improve. Innovative features of the BioSense 2.0 application include the use of cloud technology, a novel and flexible data sharing feature, a community driven approach, enhanced algorithms, and no cost statistical analysis tools available in the cloud. Each of these features will be discussed during the presentation.

Chester, Kelley G.

2013-01-01

240

Platform Independent Perseus 2.0  

NSDL National Science Digital Library

The Perseus Project at Tufts University (discussed in the October 17, 1997 Scout Report) is an ongoing initiative to create a comprehensive, interactive, multimedia digital library for the study of Archaic and Classical Greece. In 1998, the Perseus Project released a free beta version of Platform Independent Perseus 2.0. PIP2 is a graphical user interface for the Perseus 2.0 database, the latest version of the digital library. Once users install the interface locally, they may seamlessly access and navigate the numerous texts, maps, and images available on the Perseus server via an Internet connection. The benefit of PIP2 is that users are provided with a specialized interface for the online database and are able to avoid the annoying encumbrances encountered when using an unwieldy Web browser. Installation requirements and downloading instructions are posted at the site for both Mac and Windows operating systems.

1998-01-01

241

Quantifying sea surface temperature ranges of the Arabian Sea for the past 20 000 years  

NASA Astrophysics Data System (ADS)

The oxygen isotopic composition of planktonic foraminifera tests is one of the widest used geochemical tools to reconstruct past changes of physical parameters of the upper ocean. It is common practice to analyze multiple individuals from a mono-specific population and assume that the outcome reflects a mean value of the environmental conditions during calcification of the analyzed individuals. Here we present the oxygen isotope composition of individual specimens of the surface dwelling species Globigerinoides ruber and Globigerina bulloides from sediment cores in the Western Arabian Sea off Somalia inferred as indicators of past seasonal ranges in temperature. Combining the ?18O measurements of individual specimens to obtain temperature ranges with Mg/Ca based mean calcification temperatures allows us to reconstruct temperature extrema. Our results indicate that over the past 20 kyrs the seasonal temperature range has fluctuated from its present value of 16 C (14 to 30 C), to 11 C (15 to 26 C) during the LGM. The range during the LGM suggests that the maximum temperature was lower, whilst minimum temperature remained approximately constant.

Ganssen, G.; Peeters, F.; Metcalfe, B.; Anand, P.; Jung, S.; Kroon, D.; Brummer, G.-J.

2010-12-01

242

250keV Ar 2+ ion beam induced grain growth in tin oxide thin films  

Microsoft Academic Search

Nanocrystalline tin oxide (SnO2) thin films of 200nm thickness were deposited on quartz and sapphire substrates by e-beam evaporation method. The substrate temperature was kept at 200C to enhance the surface diffusion of the atoms. The films were characterized by atomic force microscopy (AFM), glancing angle X-ray diffraction (GAXRD) and UV-visible spectroscopy for morphological, structural and optical characterization respectively. The

T. Mohanty; S. Dhounsi; P. Kumar; A. Tripathi; D. Kanjilal

2009-01-01

243

Study of steel crack resistance under dynamic loading and temperature range 20-300 C  

NASA Astrophysics Data System (ADS)

The paper describes an experimental technique to measure crack resistance (plane stress-intensity factor) K1C of structural materials at loading rates up to 2.106 MPa.m1/2.s-1 and temperatures 20-300 C. This technique is based on the known Kolsky method using split Hopkinson bars. The tests were performed using compact WOL-specimens of steel St.3.

Novikov, S. A.; Pushkov, V. A.

1996-05-01

244

Collisionally excited few-electron systems: theoretical introduction and survey. [2-200 keV  

SciTech Connect

We consider excitation, ionization, and charge transfer in collisions of protons (and antiprotons) with the single-electron targets H, He/sup +/, and Li/sup 2 +/. These collisions are first compared to other types of ion-atom collisions. A brief review of our own theoretical method is given; in particular we describe how we allow for both large charge transfer and ionization probabilities while retaining the computational efficiency that allows us to consider a variety of collision partners and collision energies. We comment on the comparison of our results to other theoretical work and to experiment. The qualitative features of the various inelastic cross sections are discussed, in particular how they scale with collision energy, target nuclear charge, and the sign of the projectile charge. 15 references, 6 figures.

Ford, A.L.; Reading, J.F.; Becker, R.L.

1982-01-01

245

Range parameters of heavy ions implanted into Be films  

NASA Astrophysics Data System (ADS)

Range profiles of Bi, Pb, Eu, Cs and Cu implanted into Be films at energies from 20 to 300 keV, have been determined using Rutherford backscattering analysis. Comparison of the experimental results with the Monte Carlo TRIM calculations shows: (1) the Bi, Pb and Cu ranges in Be are larger than the predicted ones, the discrepancies being about 25%, (2) the Eu, Cs and Rb ranges are reproduced quite well by the calculations.

Grande, P. L.; Behar, M.; Biersack, J. P.; Zawislak, F. C.

1990-01-01

246

Cyberinfrastructure and Web 2.0  

Microsoft Academic Search

We review the emergence of a diverse collection of modern Internet- scale programming approaches, collectively known as Web 2.0, and compare these to the goals of cyberinfrastructure and e-Science. e-Science has had success following the Enterprise development model, which emphasizes sophisticated XML formats, WSDL and SOAP-based Web Services, complex server-side programming tools and models, and qualities of service such as

Marlon E. PIERCE; Geoffrey FOX; Huapeng YUAN

247

OSUIF: SUIF 2.0 With Objects  

Microsoft Academic Search

. OSUIF is an extension to SUIF 2.0 that provides support for the compilation of object-oriented languages.OSUIF extends standard SUIF in three main areas: symbol table, intermediate language, and exception handling. Theresulting system should be able to support compilers for many (but not all) object-oriented languages. The two initialOSUIF front ends will support C++ and Java.1. IntroductionThe original SUIF system

Andrew Duncan; Bogdan Cocosel; Costin Iancu; Holger Kienle; Radu Rugina Urs

1997-01-01

248

Clustering the Web 2.0  

Microsoft Academic Search

Ryszard Michalski has been the pioneer of Machine Learning. His conceptual clustering focused on the understandability of\\u000a clustering results. It is a key requirement if Machine Learning is to serve users successfully. In this chapter, we present\\u000a two approaches to clustering in the scenario of Web 2.0 with a special concern of understandability in this new context. In\\u000a contrast to

Katharina Morik; Michael Wurst

2010-01-01

249

Quantifying sea surface temperature ranges of the Arabian Sea for the past 20 000 years  

NASA Astrophysics Data System (ADS)

The oxygen isotopic composition of planktonic foraminifera tests is one of the widest used geochemical tools to reconstruct past changes of physical parameters of the upper ocean. It is common practice to analyze multiple individuals from a mono-specific population and assume that the outcome reflects a mean value of the environmental conditions during calcification of the analyzed individuals. Here we present the oxygen isotope composition of individual specimens of the surface-dwelling species Globigerinoides ruber and Globigerina bulloides from sediment cores in the Western Arabian Sea off Somalia, inferred as indicators of past seasonal ranges in temperature. Combining the ?18O measurements of individual specimens to obtain temperature ranges with Mg/Ca based mean calcification temperatures allows us to reconstruct temperature extrema. Our results indicate that over the past 20 kyr the seasonal temperature range has fluctuated from its present value of 16 C to mean values of 13 C and 11 C for the Holocene and LGM, respectively. The data for the LGM suggest that the maximum temperature was lower, whilst minimum temperature remained approximately constant. The rather minor variability in lowest summer temperatures during the LGM suggests roughly constant summer monsoon intensity, while upwelling-induced productivity was lowered.

Ganssen, G. M.; Peeters, F. J. C.; Metcalfe, B.; Anand, P.; Jung, S. J. A.; Kroon, D.; Brummer, G.-J. A.

2011-12-01

250

Using Web 2.0 for learning in the community  

Microsoft Academic Search

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

Robin Mason; Frank Rennie

2007-01-01

251

Using Web 2.0 for Learning in the Community  

ERIC Educational Resources Information Center

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

Mason, Robin; Rennie, Frank

2007-01-01

252

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

Microsoft Academic Search

This paper discusses the latest progress in the development of GRAPE\\u000a(Gamma-Ray Polarimeter Experiment), a hard X-ray Compton Polarimeter. The\\u000apurpose of GRAPE is to measure the polarization of hard X-rays in the 50-300\\u000akeV energy range. We are particularly interested in X-rays that are emitted\\u000afrom solar flares and gamma-ray bursts (GRBs). Accurately measuring the\\u000apolarization of the emitted

J. S. Legerea; P. Bloser; J. R. Macri; M. L. McConnella; T. Narita; J. M. Ryan

2005-01-01

253

41 CFR 60-20.2 - Recruitment and advertisement.  

Code of Federal Regulations, 2013 CFR

...Management 1 2013-07-01 2013-07-01 false Recruitment and advertisement. 60-20.2 Section 60-20.2...LABOR 20-SEX DISCRIMINATION GUIDELINES § 60-20.2 Recruitment and advertisement. (a) Employers engaged in...

2013-07-01

254

Solar Fuels and Carbon Cycle 2.0 (Carbon Cycle 2.0)  

SciTech Connect

Paul Alivisatos, LBNL Director speaks at the Carbon Cycle 2.0 kick-off symposium Feb. 4, 2010. We emit more carbon into the atmosphere than natural processes are able to remove - an imbalance with negative consequences. Carbon Cycle 2.0 is a Berkeley Lab initiative to provide the science needed to restore this balance by integrating the Labs diverse research activities and delivering creative solutions toward a carbon-neutral energy future. http://carboncycle2.lbl.gov/

Alivisatos, Paul

2010-02-04

255

W3C: XHTML 2.0  

NSDL National Science Digital Library

Web developers will be especially interested in this sneak peek at the next incarnation of the Extensible HyperText Markup Language (XHTML). This is the seventh working draft of the XHTML 2.0 specification produced by the World Wide Web Consortium, an organization that creates standards that maintain interoperability. As can be seen from the list of issues, many unresolved points remain in the specification. However, the progress that has already been made is well documented and shows how the language is evolving.

2005-01-01

256

Inverse mean free path, stopping power, CSDA range, and straggling in aluminum and aluminum oxide for electrons of energy 10 keV  

Microsoft Academic Search

The interaction of electrons with the solids Al and Al2O3 is described based on the electron gas model for the conduction band electrons in Al, a model insulator theory for the valence electrons in Al2O3, and inner shell ionization derived from atomic, generalized oscillator strengths. Contributions to the inverse mean free path and stopping power from the various interaction processes

J. C. Ashley; C. J. Tung; W. E. Anderson; R. H. Ritchie

1975-01-01

257

Inverse mean free path, stopping power, CSDA range, and straggling in silicon and silicon dioxide for electrons of energy less than or equal to 10 keV  

Microsoft Academic Search

The interaction of electrons with the solids Si and SiO2 is described based on a 'modified electron gas model' for the valence band electrons in Si, a model insulator theory for the valence band electrons in SiO2, and inner shell ionization derived from atomic, generalized oscillator strengths. Contributions to the inverse mean free path and stopping power from the various

C. J. Tung; J. C. Ashley; V. E. Anderson; R. H. Ritchie

1976-01-01

258

A new international geostationary electron model: IGE-2006, from 1 keV to 5.2 MeV  

NASA Astrophysics Data System (ADS)

Dpartement Environnement Spatial, Office National d'Etudes et de Recherches Arospatiales (ONERA) has been developing a model for the geostationary electron environment since 2003. Until now, this model was called Particle ONERA-LANL Environment (POLE), and it is valid from 30 keV up to 5.2 MeV. POLE is based on the full complement of Los Alamos National Laboratory geostationary satellites, covers the period 1976-2005, and takes into account the solar cycle variation. Over the period 1976 to present, four different detectors were flown: charged particle analyzer (CPA), synchronous orbit particle analyzer (SOPA), energetic spectra for particles (ESP), and magnetospheric plasma analyzer (MPA). Only the first three were used to develop the POLE model. Here we extend the energy coverage of the model to low energies using MPA measurements. We further include the data from the Japanese geostationary spacecraft, Data Relay Test Satellite (DRTS). These data are now combined into an extended geostationary electron model which we call IGE-2006.

Sicard-Piet, A.; Bourdarie, S.; Boscher, D.; Friedel, R. H. W.; Thomsen, M.; Goka, T.; Matsumoto, H.; Koshiishi, H.

2008-07-01

259

Compact range test applications, phase 2  

NASA Astrophysics Data System (ADS)

Georgia Tech Research Institute (GTRI) has designed and fabricated a large outdoor Compact Antenna Range for the U.S. Army Electronic Proving Ground (USAEPG). This range enables USAEPG to test antenna systems of large ground vehicles or aircraft that weigh up to 70 tons and are up to 50 feet in size over a frequency range of 6 to 40 GHz. Ongoing investigation and study are being conducted to determine the compatibility and adaptability of this antenna pattern measurement range to measure other system parameters such as target return signals and system responses to specialized electromagnetic environments.

Davis, Francis L.

1992-01-01

260

Comparison between an event-by-event Monte Carlo code, NOREC, and ETRAN for electron scaled point kernels between 20keV and 1MeV  

Microsoft Academic Search

An event-by-event Monte Carlo code called NOREC, a substantially improved version of the Oak Ridge electron transport code\\u000a (OREC), was released in 2003, after a number of modifications to OREC. In spite of some earlier work, the characteristics\\u000a of the code have not been clearly shown so far, especially for a wide range of electron energies. Therefore, NOREC was used

Sang Hyun Cho; Oleg N. Vassiliev; John L. Horton Jr

2007-01-01

261

Density matrices of the excited H (n = 2 and 3) atoms formed in 25--100-keV proton-helium charge-transfer collisions  

SciTech Connect

We present ab initio calculations for the differential and integrated (over impact parameters) density matrices of the excited hydrogen atoms (n = 2 and 3 manifolds) formed in 25--100-keV proton-helium charge-transfer collisions. The transition amplitudes for excited states are determined in a modified two-center atomic-orbital-expansion approach within the close-coupling treatment. The target helium atom is described in a one-electron picture. The calculated partial (nlm) and total charge-transfer cross sections are in good agreement with earlier theoretical and experimental data in this energy range. From the scattering amplitudes, the integrated density matrix and its various first-order moments for the n = 3 manifold are compared with recent measurements. From the three-dimensional charge-density plots, it is illustrated that the captured electron lags behind the projectile in the present energy range. From the impact-parameter-dependent density-matrix analysis, an approximate ''classical'' picture of the captured electron is presented.

Jain, A.; Lin, C.D.; Fritsch, W.

1987-09-01

262

Collective Variable Range Hopping in 2-D  

NASA Astrophysics Data System (ADS)

We have measured resistance v. temperature in ultra-thin quench-condensed metal films. Far from the metal-insulator transition, in the early stages of growth, all of our films exhibit the exponential form R?exp(T_o/T)^x, with x=0.8 0.03. Due to a logarithmic interaction between electrons in 2-D, we can map a theory for vortex hopping in a superconductor by Fisher et al.(M. P. A. Fisher et. al.), Phys. Rev. Lett. 66, 2931 (1991). onto the problem of electron hopping. The long-range interaction results in a reduction of energy for a single hop if surrounding electrons also hop. If the number of electrons participating in this collective hop are contained in an area whose radius is the hopping distance, the theory gives x=4/5, in good agreement with our data. Preprint.

Grupp, Daniel E.; Martinez, G.; Markovic, N.; Mack, A. M.; Glazman, L.; Goldman, A. M.

1998-03-01

263

Inverse mean free path, stopping power, CSDA range, and straggling in Ge and GaAs for electrons of energy 10 keV  

Microsoft Academic Search

The interaction of electrons with the solids Ge and GaAs is described, based on a model insulator theory for the valence band electrons and inner shell ionization derived from classical-binary-collision cross sections. Contributions to the inverse mean free path and stopping power from the various interaction processes are tabulated for electron energies from threshold, approximately 2 eV for Ge and

J. C. Ashley; C. J. Tung; R. H. Ritchie; V. E. Anderson

1976-01-01

264

Transmission images and evaluation of tomographic imaging based scattered radiation from biological materials using 10, 15, 20 and 25 keV synchrotron X-rays: An analysis in terms of optimum energy  

NASA Astrophysics Data System (ADS)

Transmission images and tomographic imaging based scattered radiation is evaluated from biological materials, for example, Polyethylene, Poly carbonate, Plexiglas and Nylon using 10, 15, 20 and 25 keV synchrotron X-rays. The SYRMEP facility at Elettra,Trieste, Italy and the associated detection system has been used for the image acquisition. The scattered radiation is detected for each sample at three energies at an angle of 90 using Si-Pin detector coupled to a multi-channel analyzer. The contribution of transmitted, Compton and fluorescence photons are assessed for a test phantom of small dimensions. The optimum analysis is performed with the use of the dimensions of the sample and detected radiation at various energies.

Rao, Donepudi V.; Akatsuka, Takao; Tromba, Giuliana

2004-05-01

265

Transmission images and evaluation of tomographic imaging based scattered radiation from biological materials using 10, 15, 20 and 25 keV synchrotron X-rays: An analysis in terms of optimum energy  

SciTech Connect

Transmission images and tomographic imaging based scattered radiation is evaluated from biological materials, for example, Polyethylene, Poly carbonate, Plexiglas and Nylon using 10, 15, 20 and 25 keV synchrotron X-rays. The SYRMEP facility at Elettra,Trieste, Italy and the associated detection system has been used for the image acquisition. The scattered radiation is detected for each sample at three energies at an angle of 90 deg. using Si-Pin detector coupled to a multi-channel analyzer. The contribution of transmitted, Compton and fluorescence photons are assessed for a test phantom of small dimensions. The optimum analysis is performed with the use of the dimensions of the sample and detected radiation at various energies.

Rao, Donepudi V. [Synchrotron Radiation for Medical Physics, Elettra, Trieste (Italy); Akatsuka, Takao [Dept of Bio-System Engineering, Faculty of Engineering, Yamagata University, 4-3-16 Jonan, Yonezawa 992-8510 (Japan); Tromba, Giuliana [Department of Physics, Sir. C.R.R. Autonomous College, Eluru-534007., W.G. Dt., A. P. (India)

2004-05-12

266

A study of inclusive photoproduction of hyperons and antihyperons in the range of 20 to 70 GeV  

Microsoft Academic Search

Results are presented on inclusive photoproduction in hydrogen of Sigma0, Sigma1385+\\/-, Xi-0, and their antiparticles for incident energies between 20 and 70 GeV. Hyperons and antihyperons are mainly measured in the kinematical range of central and forward production (xF > -0.3). We find the cross-section ratios sigma(Sigma1385+)\\/sigma(Sigma1385-) = 1.4 +\\/- 0.1, sigma(Sigma1385+)\\/sigma(Sigma1385-) = 1.3 +\\/- 0.2 and an antiparticle\\/particle ratio

D. Aston; M. Atkinson; R. Bailey; A. K. Ball; H. J. Bautsch; B. Bouquet; G. R. Brookes; J. Brring; Peter J Bussey; D. Clarke; A. B. Clegg; B. D'Almagne; G. de Rosny; B. Diekmann; Alexander Donnachie; M. Draper; B. Drevillon; I. P. Duerdoth; J.-P. Dufey; R. J. Ellison; D. Ezra; P. Feller; A. Ferrer; P. J. Flynn; William Galbraith; R. George; S. D. M. Gill; M. Goldberg; S. Goodman; W. Graves; B. Grossette; P. G. Hampson; K. Heinloth; R. E. Hughes-Jones; J. S. Hutton; M. Ibbotson; M. Jung; S. Katsanevas; M. A. R. Kemp; F. Kovacs; B. R. Kumar; G. D. Lafferty; J.-M. Lvy; V. Liebenau; John Litt; G W London; D. Mercer; J. V. Morris; K. Mller; D. Newton; E. Paul; P. Petroff; Y. Pons; C. Raine; F. Richard; R H Richter; J. H. C. Roberts; Patrick Roudeau; A. Roug; M. Rumpf; M. Sen; Ian O Skillicorn; J. C. Sleeman; K. M. Smith; C. Steinhauer; Kenneth Mick Storr; R. J. Thompson; D. Treille; Ch. de La Vaissire; H L Videau; I. Videau; A. P. Waite; A. Wijangco; W. Wojcik; J.-P. Wuthrick; T. P. Yiou

1982-01-01

267

A Future with (out) Carbon Cycle 2.0 (Carbon Cycle 2.0)  

SciTech Connect

Bill Collins, Head of LBNL's Climate Sciences Department, speaks at the Carbon Cycle 2.0 kick-off symposium Feb. 1, 2010. We emit more carbon into the atmosphere than natural processes are able to remove - an imbalance with negative consequences. Carbon Cycle 2.0 is a Berkeley Lab initiative to provide the science needed to restore this balance by integrating the Labs diverse research activities and delivering creative solutions toward a carbon-neutral energy future. http://carboncycle2.lbl.gov/

Collins, Bill

2010-02-01

268

A Call to Action: Carbon Cycle 2.0 (Carbon Cycle 2.0)  

SciTech Connect

Berkeley Lab Director Paul Alivisatos speaks at the Carbon Cycle 2.0 kick-off symposium Feb. 1, 2010. Humanity emits more carbon into the atmosphere than natural processes are able to remove - an imbalance with negative consequences.Carbon Cycle 2.0 is a Berkeley Lab initiative to provide the science needed to restore this balance by integrating the Labs diverse research activities and delivering creative solutions toward a carbon-neutral energy future. http://carboncycle2.lbl.gov/

Alivisatos, Paul

2010-02-01

269

The dissociation of 13CH and 12CH2 molecules in He and N2 at beam energies of 80-250 keV and possible implications for radiocarbon mass spectrometry  

NASA Astrophysics Data System (ADS)

Isotopic ratios of 14C at natural levels can be efficiently measured with accelerator mass spectrometry (AMS). In compact AMS systems, 13CH and 12CH2 molecular interferences are destroyed in collisions with the stripper gas, a process which can be described by dissociation cross sections. These dissociation cross sections determine the gas areal density required for sufficient attenuation of the interfering molecular beams, and are therefore key parameters in the effort to further reduce the terminal voltage and thus the size of the AMS system. We measured the dissociation cross sections of 13CH and 12CH2 in N2 and He in the energy range of 80-250 keV. In N2, cross sections were constant for energies above 100 keV with average values per molecule of (8.1 0.4) 10-16 cm2 for 13CH and (9.5 0.5) 10-16 cm2 for 12CH2. In He, cross sections were constant over the full measured range of 80-150 keV with average values of (4.2 0.3) 10- 16 cm2 and (4.8 0.4) 10-16 cm2, respectively. A considerable reduction of the terminal voltage from the currently used 200 kV while using N2 for 13CH and 12CH2 molecule dissociation is not possible: the required N2 areal densities of 1.4 ?g/cm2, consequential angular straggling and a decreasing 1+ charge state fraction would reduce the ion beam transmission too much. This is not the case for He: sufficient molecule dissociation can be obtained with gas densities of 0.4 ?g/cm2, for which angular straggling is relatively small. In addition, the 1+ charge state fraction still increases at lower stripping energies. Thus, the usage of He for stripping and molecule dissociation might allow the development of even smaller 14C-AMS systems than available today.

Schulze-Knig, T.; Seiler, M.; Suter, M.; Wacker, L.; Synal, H.-A.

2011-01-01

270

Analysis of 2H(vec{d}, p)3H Reaction at 30-90 KeV by Four-Body Faddeev-Yakubovsky Equation  

NASA Astrophysics Data System (ADS)

Low-energy 2H(vec{d}, p)3H reactions are investigated by the four-body Faddeev-Yakubovsky equations. Cross sections and tensor analyzing powers are calculated at 30-90 keV energies. The PEST-1 potentials are used for nucleon-nucleon interactions. The [2 + 2] and [3 + 1] subamplitudes are treated by the Hilbert-Schmidt expansions. Numerical results give qualitative explanation of experimental data.

Uzu, E.; Oryu, S.; Tanifuji, M.

1993-10-01

271

Molecular dynamics simulations of the initial stages of sputter erosion of a metal overlayer system: 2 keV Ar --> Cu\\/Ni(1 0 0)  

Microsoft Academic Search

The initial sputter erosion of Cu\\/Ni(1 0 0) has been simulated using molecular dynamics. The morphological and compositional changes that accompany sputtering are described. Ar projectiles (2 keV) are delivered sequentially at 10 ps intervals into a 2000 2 region of the target, up to a nominal fluence of 1.1 1015 cm-2. Simulations were performed for several projectile target

M. A. Karolewski

2006-01-01

272

Molecular dynamics simulations of the initial stages of sputter erosion of a metal overlayer system: 2 keV Ar ? Cu\\/Ni(1 0 0)  

Microsoft Academic Search

The initial sputter erosion of Cu\\/Ni(100) has been simulated using molecular dynamics. The morphological and compositional changes that accompany sputtering are described. Ar projectiles (2keV) are delivered sequentially at 10ps intervals into a 20002 region of the target, up to a nominal fluence of 1.11015cm?2. Simulations were performed for several projectiletarget geometries with normal, oblique and random altitudinal (?) angles

M. A. Karolewski

2006-01-01

273

Comparative interactomics with Funcoup 2.0.  

PubMed

FunCoup (http://FunCoup.sbc.su.se) is a database that maintains and visualizes global gene/protein networks of functional coupling that have been constructed by Bayesian integration of diverse high-throughput data. FunCoup achieves high coverage by orthology-based integration of data sources from different model organisms and from different platforms. We here present release 2.0 in which the data sources have been updated and the methodology has been refined. It contains a new data type Genetic Interaction, and three new species: chicken, dog and zebra fish. As FunCoup extensively transfers functional coupling information between species, the new input datasets have considerably improved both coverage and quality of the networks. The number of high-confidence network links has increased dramatically. For instance, the human network has more than eight times as many links above confidence 0.5 as the previous release. FunCoup provides facilities for analysing the conservation of subnetworks in multiple species. We here explain how to do comparative interactomics on the FunCoup website. PMID:22110034

Alexeyenko, Andrey; Schmitt, Thomas; Tjrnberg, Andreas; Guala, Dmitri; Frings, Oliver; Sonnhammer, Erik L L

2011-11-21

274

Schwinger variational approach for a direct excitation of hydrogen-like (Li2+ (1s)) target to the level n=3 by proton impact energies from 9 keV to 3 MeV  

NASA Astrophysics Data System (ADS)

The excitation cross sections for hydrogen-like (Li2+(1s)) to the 3s, 3p and 3d states by proton impact have been calculated in a wide energy range from 9 keV to 3 MeV, using the Schwinger's variational principle within the impact parameter formalism. These cross sections are relevant to controlled nuclear fusion studies [1]. The behaviors of the computed cross sections are in excellent agreement with available theoretical results, obtained by close-coupling method which is those of TCAO of Ermolaev et al [1] and SCE of Hall et al [2].

Khelfaoui, Friha; Lasri, Boumediene; Abbes, Oukacha

2012-06-01

275

New space research frequency band proposals in the 20- to 40.5-GHz range  

NASA Astrophysics Data System (ADS)

Future space research communications systems may require spectra above 20 GHz. Frequency bands above 20 GHz are identified that are suitable for space research. The selection of the proper bands depends on consideration of interference with other radio services, adequate bandwidths, link performance, and technical requirements for practical implementation.

Bishop, D. F.

1991-02-01

276

30 CFR 20.2 - Definitions.  

Code of Federal Regulations, 2013 CFR

...design formally approved by MSHA under this part. (Approvals under this part are given only to equipment for use in gassy and dusty mines.) [Sched. 10C, May 17, 1938, as amended by Supp. 1, 20 FR 2718, Apr. 23,...

2013-07-01

277

A Medium Survey of the Hard X-Ray Sky with the ASCA Gas Imaging Spectrometer: The (2--10 keV) Number Counts Relationship  

Microsoft Academic Search

In this paper, we report the first results of a medium survey program conducted in the 2-10 keV energy band using data from the GIS2 instrument onboard the ASCA satellite. We have selected from the ASCA public archive (as of 1996 February 14) 87 images suitable for this project. Sixty serendipitous X-ray sources with a signal-to-noise ratio greater than 3.5

I. Cagnoni; R. della Ceca; T. Maccacaro

1998-01-01

278

Toward spam 2.0: An evaluation of Web 2.0 anti-spam methods  

Microsoft Academic Search

Spammers have proven very powerfully adaptable, if we thwart all current spam methods, they will find new loophole to use them. Blogs, comments, forums, opinions, online communities, wikis and tags are nowadays targets for their campaigns. This paper presents analysis of current anti-spam methods in Web 2.0 for spam detection and prevention against our proposed evaluation framework. The framework is

Pedram Hayati; Vidyasagar Potdar

2009-01-01

279

Enabling Problem Based Learning through Web 2.0 Technologies: PBL 2.0  

ERIC Educational Resources Information Center

|Advances in Information and Communications Technology (ICT), particularly the so-called Web 2.0, are affecting all aspects of our life: How we communicate, how we shop, how we socialise, how we learn. Facilitating learning through the use of ICT, also known as eLearning, is a vital part of modern educational systems. Established pedagogical

Tambouris, Efthimios; Panopoulou, Eleni; Tarabanis, Konstantinos; Ryberg, Thomas; Buus, Lillian; Peristeras, Vassilios; Lee, Deirdre; Porwol, Lukasz

2012-01-01

280

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

ERIC Educational Resources Information Center

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

Arya, Harsh Bardhan; Mishra, J. K.

2012-01-01

281

Long-range and short-range orderings in K4Fe4P5O20 with a natrolite-like framework.  

PubMed

K4Fe4P5O20 shows an interesting natrolite-like structure with a spin-tetrahedron lattice built by mixed valence Fe ions. Single crystals of the title compound are successfully grown by the flux method using KF as flux. Magnetic results combined from magnetic, heat capacity, and (57)Fe Mssbauer spectra measurements show that K4Fe4P5O20 possesses a short-range magnetic ordering at ?13 K and a long-range ordering at ?7 K. Magnetic anisotropy of K4Fe4P5O20 is observed between H?c and H?c, suggesting that the c-axis is the magnetic easy-axis. The spin arrangements in the system are suggested to be ferrimagnetic along the natrolite chains. PMID:23455398

He, Zhangzhen; Zhang, Weilong; Cheng, Wendan; Okazawa, Atsushi; Kojima, Norimichi

2013-04-28

282

G-Factors of the 264 KeV and 632 KeV States in exp 77 As.  

National Technical Information Service (NTIS)

The integral perturbed angular correlation technique has been used to measure the g-factors of the 264 keV and 632 keV nuclear levels in exp 77 As. The g-factor of the 264 keV (5/2 exp - ) state with tau = 450+-30 ps was determined through the 367-264 keV...

F. C. Zawislak J. Schaf J. M. Gualda R. N. Saxena R. P. Livi

1978-01-01

283

Web 2.0 and Critical Information Literacy  

ERIC Educational Resources Information Center

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

Dunaway, Michelle

2011-01-01

284

Chemical and icosahedral short-range orders in liquid and undercooled Al80Mn20 and Al80Ni20 alloys: A first-principles-based approach  

NASA Astrophysics Data System (ADS)

Atomic structures of stable liquid and undercooled liquid Al80Mn20 and Al80Ni20 alloys have been calculated by first-principles molecular-dynamics simulations. For both alloys, the local structure as defined by the Faber-Ziman pair-correlation functions is characterized by a strong Al-transition-metal affinity, which leads to a well-pronounced chemical short-range order which is more temperature dependent for Al80Mn20 than for Al80Ni20. In addition, a structural analysis using three-dimensional pair analysis techniques has been performed in details. More particularly, we find that the fivefold local symmetry around Mn atoms is predominant in both stable and undercooled Al80Mn20 alloys and displays no significant variation with temperatures. On the contrary, in Al80Ni20, a strong variation of the topological short-range order is observed since in the undercooled state, the local environment of Ni atoms is characterized by the predominance of the fivefold symmetry over the close-packed local symmetry which is opposed to what occurs in the stable liquid phase.

Jakse, N.; Le Bacq, O.; Pasturel, A.

2005-09-01

285

20 CFR 418.1115 - What are the modified adjusted gross income ranges?  

Code of Federal Regulations, 2013 CFR

...income ranges? 418.1115 Section 418.1115 Employees' Benefits SOCIAL SECURITY ADMINISTRATION MEDICARE SUBSIDIES Medicare Part B Income-Related Monthly Adjustment Amount Determination of the Income-Related Monthly...

2013-04-01

286

WHURLE 2.0: Adaptive Learning Meets Web 2.0  

Microsoft Academic Search

The adoption of Adaptive Educational Hypermedia Systems into real world teaching has been poor so far. One of the reasons\\u000a behind this is believed to be due to their architectural design failing to answer the overall needs of Web-enhanced learning.\\u000a On the other hand, Web 2.0 emerging technologies are transforming the whole field of e-Learning into one known as e-Learning

Maram Meccawy; Peter Blanchfield; Helen Ashman; Tim J. Brailsford; Adam Moore

2008-01-01

287

Stopping power and mean free path for low-energy electrons in ten scintillators over energy range of 20-20,000 eV.  

PubMed

Systematic calculations of the stopping powers (SP) and inelastic mean free paths (IMFP) for 20-20,000eV 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 20-20,000eV, and are of key importance for the investigation of liquid scintillation counting. PMID:21880497

Tan, Zhenyu; Xia, Yueyuan

2011-08-22

288

Unique Spectral Features Search In The 20 - 35 Micron Range of Mgs Tes Data  

Microsoft Academic Search

TES is the Thermal Emission Spectrometer aboard the NASA mission Mars Global Surveyor (MGS) orbiting around Mars since September 1997. It is collecting 6 - 50 micron thermal emission spectra and one of its principal purposes is to determine and map the Mars surface composition. Spectral features directly ascribable to sur- face minerals have been identified in the 20 -

F. Altieri; G. Bellucci

2002-01-01

289

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.  

PubMed

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. PMID:20515133

Hubert, S; Dubois, J L; Gontier, D; Lidove, G; Reverdin, C; Soulli, G; Stemmler, P; Villette, B

2010-05-01

290

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  

SciTech Connect

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.

Hubert, S.; Dubois, J. L. [Commissariat a l'Energie Atomique, DAM, CESTA, BP 2, Le Barp 33114 (France); Gontier, D.; Lidove, G.; Reverdin, C.; Soullie, G.; Stemmler, P.; Villette, B. [Commissariat a l'Energie Atomique, DAM, DIF, Arpajon F-91290 (France)

2010-05-15

291

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  

NASA Astrophysics Data System (ADS)

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.

Hubert, S.; Dubois, J. L.; Gontier, D.; Lidove, G.; Reverdin, C.; Soulli, G.; Stemmler, P.; Villette, B.

2010-05-01

292

SHOCK 2.0 Theory Manual.  

National Technical Information Service (NTIS)

SHOCK is a computer program that implements the method used to generate Figures 2-52 through 2-100 for averaged reflected pressure and Figures 2- 101 through 2-149 for reflected impulse in UFC 3-340-02 Structures to Resist the Effects of Accidental Explos...

C. Stewart J. Abraham

2011-01-01

293

Recent plant studies using Victoria 2.0  

SciTech Connect

VICTORIA 2.0 is a mechanistic computer code designed to analyze fission product behavior within the reactor coolant system (RCS) during a severe nuclear reactor accident. It provides detailed predictions of the release of radioactive and nonradioactive materials from the reactor core and transport and deposition of these materials within the RCS and secondary circuits. These predictions account for the chemical and aerosol processes that affect radionuclide behavior. VICTORIA 2.0 was released in early 1999; a new version VICTORIA 2.1, is now under development. The largest improvements in VICTORIA 2.1 are connected with the thermochemical database, which is being revised and expanded following the recommendations of a peer review. Three risk-significant severe accident sequences have recently been investigated using the VICTORIA 2.0 code. The focus here is on how various chemistry options affect the predictions. Additionally, the VICTORIA predictions are compared with ones made using the MELCOR code. The three sequences are a station blackout in a GE BWR and steam generator tube rupture (SGTR) and pump-seal LOCA sequences in a 3-loop Westinghouse PWR. These sequences cover a range of system pressures, from fully depressurized to full system pressure. The chief results of this study are the fission product fractions that are retained in the core, RCS, secondary, and containment and the fractions that are released into the environment.

BIXLER,NATHAN E.; GASSER,RONALD D.

2000-03-08

294

50 CFR 30.2 - Disposition of surplus range animals.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 false Disposition of surplus range animals. 30.2 Section 30...Range Animals § 30.2 Disposition of surplus range animals. Disposition shall...existence of exigent circumstances. Surplus range animals may be disposed...

2011-10-01

295

50 CFR 30.2 - Disposition of surplus range animals.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 false Disposition of surplus range animals. 30.2 Section 30...Range Animals § 30.2 Disposition of surplus range animals. Disposition shall...existence of exigent circumstances. Surplus range animals may be disposed...

2012-10-01

296

Web Content Accessibility Guidelines 2.0  

NSDL National Science Digital Library

Dated August 24, 2001, this online working draft of Web content accessibility guidelines comes from the World Wide Web Consortium (WC3). The aim of this accessibility project is to make Web more navigable to people with disabilities. The first draft of the guidelines was published in 1999 (mentioned in the May 7, 1999 Scout Report). This newer version incorporates reader feedback, covers a wider range of technologies and uses wording that may be understood by a more varied audience. Four guidelines, each containing several "checkpoints," an introduction and glossary are included. A hypertext Table of Contents takes readers to desired sections.

Vanderheiden, Gregg C., 1949-; White, Jason.; Chisholm, Wendy.

2001-01-01

297

High spectral resolution Al2O3/B4C, SiC/Si, SiC/B4C, and SiC/C multilayer structures for the photon energies of 6 keV to 19 keV  

NASA Astrophysics Data System (ADS)

A double multilayer monochromator with each multilayer composed of four stripes with different d-spacing providing spectral resolution of 0.3% to 0.8% in the energy range of 6keV to 19keV has been developed. Test multilayer structures with d-spacing from 2.3nm to 10.6nm have been deposited by magnetron sputtering. X-ray characterization has been performed at OSMIC by using a recently upgraded diffractometer setup and Cu-K? radiation and at the APS. The following material combinations were studied before the final choice of materials for the high energy resolution monochromator has been made: Al2O3/B4C, SiC/Si, SiC/B4C and SiC/C. To minimize the effect of internal stress built in multilayer structure on X-ray characteristics flat and thick 1" diameter silicon substrates supplied by Wave Precision Inc. were used for all calibration coatings. Final coatings were deposited on two 145mm long, 60mm wide and 30mm thick silicon substrates. Resolution of SiC/Si structures with d1=2.3nm, N1=1000 and d2=3nm, N2=700 was measured at Cu-K? with X-ray beam divergence of 14 arcsec to be 0.216% and 0.34% respectively. For plane waves the resolution is expected to be 0.13% and 0.19%, respectively.

Platonov, Yuriy Y.; Martynov, Vladimir V.; Kazimirov, Alexander; Lai, Barry

2004-11-01

298

An integrated 20 GHz SiGe bipolar differential oscillator with high tuning range  

Microsoft Academic Search

A fully integrated, differential LC oscillator manufactured in Infineon's B7HF SiGe bipolar technology with an fT and fmax of 75 GHz is presented. The oscillator features a tank consisting of on-chip stripline inductors and the parasitic capacitances of the oscillator transistors. A tuning range of 14-21.5 GHz over bias current is achieved. The output buffer is inductively coupled to the

Klaus Ettinger; Markus Bergmayr; Harald Pretl; Wolfgang Thomann; Josef Fenk; Robert Weigel

2000-01-01

299

Solar Advisor Model User Guide for Version 2.0  

SciTech Connect

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

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

2008-08-01

300

Primary cosmic ray spectra in the range 20-60 GeV/n  

NASA Astrophysics Data System (ADS)

Energy spectra for primary cosmic rays C-Fe above 20 GeV/n were measured on a balloon flight from Greenville S.C. in June 1982 with a hybrid electronic counter-emulsion chamber experiment. Fluxes above the atmosphere appear in general agreement with previously published values. The heavy events included in this data will be used along with the JACEE passive chamber data to provide a heavy composition direct measurement from 10 to the 12th power to approximately 10 to the 15th power eV total energy.

Burnett, T. H.; Dake, S.; Derrickson, J. H.; Fuki, M.; Fountain, W. F.; Gregory, J. C.; Hayashi, T.; Hayashi, T.; Holynski, R.; Iwai, J.; Jones, W. V.

1985-08-01

301

Icosahedral short-range order in amorphous Cu80Si20 by ab initio molecular dynamics simulation study  

SciTech Connect

Short-range order in liquid and amorphous structures of Cu80Si20 is studied by ab initio molecular dynamics simulations. We performed the simulations at 1140 and 300 K respectively to investigate the local structure change from liquid to amorphous. The result of structure factor in comparison with experimental data indicates that our simulation of amorphous Cu80Si20 is reliable. By using the bond-angle distribution function, HoneycuttAndersen index, Voronoi tessellation method, and the atomistic cluster alignment method, the icosahedral short-range order in the system is revealed. Strong CuSi interaction was also observed.

Wu, S.; Kramer, Matthew J.; Fang, Xiaowei; Wang, Shy-Guey; Wang, Cai-Zhuang; Ho, Kai-Ming; Ding, Z.J.; Chen, L.Y.

2012-04-26

302

Latitude variation of recurrent MeV-energy proton flux enhancements in the heliocentric radial range 11 t 20 AU and possible correlation with solar coronal hole dynamics  

Microsoft Academic Search

Recurrent low energy (> or approx. =0.5 MeV) proton flux enhancements, reliable indicators of corotating plasma interaction regions in interplanetary space, have been observed on the Voyager 1 and 2 and Pioneer 11 spacecraft in the heliographic latitude range 2°S to 23°N and the heliocentric radial range 11 to 20 AU. After a period of rather high correlation between fluxes

S. P. Christon; E. C. Stone

1985-01-01

303

17 CFR 20.2 - Covered contracts.  

Code of Federal Regulations, 2013 CFR

...Blendstock (RBOB). NYMEX Hot Rolled Coil Steel. NYMEX Natural Gas. NYMEX No. 2 Heating Oil, New York Harbor. NYMEX Palladium. NYMEX Platinum. NYMEX Sugar No. 11. NYMEX Uranium. Diversified Commodity Index (See §...

2013-04-01

304

Photoproduction of KKpi final states in the photon energy range from 20 to 70 GeV  

Microsoft Academic Search

The reactions gammap-->K+K-pi0(p) and gammap--> Ks0K+\\/- pi+\\/-(p) have been measured using tagged photons in the energy range 20 to 70 GeV. No resonance structure is observed in either of the KKpi invariant mass distributions, which range from threshold up to ~ 3 GeV. The photoproduction cross sections for phipi0 and K*(892)K are presented and are compared with theoretical predictions. No

M. Atkinson; T. J. Axon; D. Barberis; T. J. Brodbeck; G. R. Brookes; J. J. Bunn; P. J. Bussey; A. B. Clegg; J. B. Dainton; M. Davenport; B. Dickinson; B. Diekmann; A. Donnachie; R. J. Ellison; P. Flower; P. J. Flynn; W. Galbraith; K. Heinloth; R. C. W. Henderson; R. E. Hughes-Jones; J. S. Hutton; M. Ibbotson; H. P. Jakob; M. Jung; M. A. R. Kemp; B. R. Kumar; J. Laberrigue; G. D. Lafferty; J. C. Lassalle; J. M. Levy; V. Liebenau; R. H. McClatchey; D. Mercer; J. A. G. Morris; J. V. Morris; D. Newton; C. Paterson; G. N. Patrick; E. Paul; C. Raine; M. Reidenbach; H. Rotscheidt; A. Schlsser; P. H. Sharp; I. O. Skillicorn; K. M. Smith; K. M. Storr; R. J. Thompson; Ch. de La Vaissire; A. P. Waite; M. F. Worsell; T. P. Yiou

1984-01-01

305

18 CFR 20.2 - Regulation of issuance of securities.  

Code of Federal Regulations, 2013 CFR

...false Regulation of issuance of securities. 20.2 Section 20.2 Conservation...Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT... AUTHORIZATION OF THE ISSUANCE OF SECURITIES BY LICENSEES AND COMPANIES...

2013-04-01

306

20 CFR 361.2 - Scope.  

Code of Federal Regulations, 2013 CFR

...POLICY AND PROCEDURES RECOVERY OF DEBTS OWED TO THE UNITED STATES GOVERNMENT BY GOVERNMENT EMPLOYEES § 361.2 Scope. ...301, et seq .), or the tariff laws of the United States; or to any case where collection of a debt by...

2013-04-01

307

20 CFR 332.2 - General considerations.  

Code of Federal Regulations, 2013 CFR

...for or laying over between regularly assigned trips or tours of duty if the day is one on which, because of pregnancy, miscarriage, or the birth of a child, (1) she is unable to work or (2) working would be injurious to her health. [Board...

2013-04-01

308

The EUROCALL Review, Volume 20, Number 2  

ERIC Educational Resources Information Center

|"The EUROCALL Review" is published online biannually by the European Association for Computer-Assisted Language Learning (EUROCALL). This issue offers regular sections on: (1) up-to-date information on Special Interest Groups; (2) reports on on-going CALL or CALL-related R&D projects in which EUROCALL members participate; (3) reports and reviews

Gimeno, Ana, Ed.

2012-01-01

309

Asymmetry and angular distribution of deuteron photodisintegration in the 20-60 MeV range  

NASA Astrophysics Data System (ADS)

Theoretical results on the asymmetry function and angular distribution parameters for deuteron photodisintegration are obtained by adding the one- and two-body relativistic corrections to the charge density and meson exchange corrections to the current density to the normal E1, M1, and E2 multipoles and compared with the recent measurements of De Pascale et al. Phenomenologically, it is found that agreement with the angular distribution coefficients which depend on the E2 transitions can be improved if the E2 radial matrix elements are reduced by about 15%. The physical process responsible for this reduction is not clear.

Rustgi, M. L.; Pandey, L. N.; Kassaee, A.

1986-05-01

310

42 CFR 2.20 - Relationship to State laws.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 false Relationship to State laws. 2.20 Section 2.20 Public Health...Provisions § 2.20 Relationship to State laws. The statutes authorizing these regulations...290dd-3) do not preempt the field of law which they cover to the exclusion of...

2011-10-01

311

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

NASA Astrophysics Data System (ADS)

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

Sakaguchi, T.; Ehara, K.

2011-02-01

312

LSST Science Book, Version 2.0  

Microsoft Academic Search

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

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

2009-01-01

313

A search for the level at 803 keV in 51Cr  

Microsoft Academic Search

The 803 keV level found in 51Cr through the 50Cr(d, p)51Cr reaction does not seem to be generated in the 51V(p, n)51Cr reaction to an intensity greater than 2% of the 747 keV level as determined by observing the direct gamma radiations with a lithium-drifted germanium detector with incident protons of energy in the range 2.310-3.100 MeV.

K. V. K. Iyengar; B. Lal; S. K. Gupta; M. D. Deshpande

1967-01-01

314

36 CFR 222.2 - Management of the range environment.  

Code of Federal Regulations, 2010 CFR

...Management of the range environment. 222.2... Grazing and Livestock Use on the National Forest...of the range environment. (a) Allotments...designated on the National Forest...be managed for livestock grazing...

2009-07-01

315

36 CFR 222.2 - Management of the range environment.  

Code of Federal Regulations, 2010 CFR

...Management of the range environment. 222.2... Grazing and Livestock Use on the National Forest...of the range environment. (a) Allotments...designated on the National Forest...be managed for livestock grazing...

2010-07-01

316

Proton Scattering from Polarized HELIUM-3 in the Energy Range from 20 TO 35 Mev.  

NASA Astrophysics Data System (ADS)

The ('3)He analyzing powers have been measured at the forward angles ((LESSTHEQ) 100(DEGREES)) and at energies of 25, 30, 32.5, and 35 MeV. A polarized ('3)He target has been built using optical pumping with ('4)He -discharge lamps. An improved version of the equations describing the balance between polarizing and depolarizing processes was developed. Polarization through excitation of alternative transitions is discussed. Among the depolarizing processes, especially the reabsorption of pumping light is considered. The experience with the polarized target in nuclear scattering experiments is described. Single energy phase shift analyses have been made using the available precise data at seven energies between 19.5 and 35 MeV. Real phases up to L = 4, imaginary phases up to L = 3, and coupling between channels with J = 1 and 2 were allowed in the analysis. Singlet and triplet waves of the same angular momentum have considerable mixing, which reaches a maximum at 31 and 28 MeV for channels with respectively J('(pi)) = 1('-) and 2('+). Mixing angles for tensor coupling were always found to be close to zero. Several ambiguities in previous phase shift analyses are clarified. Also, the real phases have a smoother energy dependence than was found before. No significant excursions in the imaginary phases could be detected.

Verheijen, Peter Joannes Theodorus

317

Recent experiments on induced gamma emission under isomeric transition 119m2Sn-119m1Sn+hv(65.66 keV)  

NASA Astrophysics Data System (ADS)

An induced gamma emission (IGE) upon the transition Sn(119 m2) + hvres(65.66 keV) yields Sn(119m1) + 2hvres was triggered in the polycrystal matrix 119m(2)SnO2 by its cooling to a temperature of 78 K. A measured relative value of the IGE output ((epsilon) (SnO2) equals 0.00014 and (epsilon) (SnO) 2)SnO2 and fM(10 K) equals 0.021 for 119m(2)SnO.

Bondarevskii, Svjatoslav I.; Dzevitskii, Boris E.; Eremin, Vjacheslav V.; Skorobogatov, German A.

1999-01-01

318

Vela X-1 observations in different orbital phases. Phase-resolved spectra in the 0.2 - 10 keV energy band and pulse profile analysis.  

NASA Astrophysics Data System (ADS)

Vela X-1 was pointed by BeppoSAX satellite during the Science Verification Phase (SVP) and in the framework of Observational Programs. The lightcurves of these observations are quite complex and includes dips and eclipses. We performed detailed phase-resolved spectral analysis in the 0.2 - 10 keV energy band. Spectral parameters as iron line energy, width and low energy absorption show clear dependence on the pulse-phase. Pulse profile structure is strongly dependent on the energy and becomes complex in the low energy part of the spectrum.

Del Sordo, S.; Orlandini, M.; Parmar, A.; Santangelo, A.; Segreto, A.; Dal Fiume, D.

2000-10-01

319

Hard X-rays QEXAFS instrumentation with scan range 20 to 4000 eV  

NASA Astrophysics Data System (ADS)

The Quick Extended Absorption Fine Structure (QEXAFS) spectroscopy was developed at the National Synchrotron Light Source (NSLS) to learn on seconds and sub-seconds time scale of the structural changes in the material. The initial system was developed at beamline X18B [1], however, two drawbacks with this original system were (1) problems with scan frequencies <0.1 Hz due to insufficient power of the DC motor and (2) rough operation at large angles due to gravity pulling on the monochromator arm, which is parallel to the beam, giving rise to different durations of low to high and high to low energy scans. The beamline was not focused so there was not enough flux to get good quality data. To overcome these problems we developed a new QEXAFS system at focused beamline X18A and changed the mechanical arrangement of data collection. The whole driving mechanism is still outside the vacuum environment and the mode of operation can be changed to conventional EXAFS in few minutes without venting the monochromator chamber.

Khalid, S.; Ehrlich, S. N.; Lenhard, A.; Clay, B.

2011-09-01

320

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

SciTech Connect

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

Furnish, M.D.

1994-12-01

321

Synthesis of gold and silver nanoparticles by electron irradiation at 5 15 keV energy  

Microsoft Academic Search

Thin coatings (~10 m) made from a mixture of polyvinyl alcohol (PVA) and HAuCl4 or PVA and AgNO3 on quartz plates were irradiated with 5-15 keV electrons, at room temperature. The electron energy was varied from coating to coating in the range of 5-15 keV, but electron fluence was kept constant at ~1015 e cm-2. Samples were characterized by the

S. K. Mahapatra; K. A. Bogle; S. D. Dhole; V. N. Bhoraskar

2007-01-01

322

36 CFR 222.2 - Management of the range environment.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Management of the range environment. 222.2 Section 222.2 Parks, Forests, and Public...National Forest System § 222.2 Management of the range environment. (a) Allotments will be designated on the...

2013-07-01

323

Turbulence eddy dissipation rates from radar observations at 5-20 km at White Sands Missile Range, New Mexico  

Microsoft Academic Search

A climatology of the eddy dissipation rate is presented based on the widths of the Doppler radar spectra observed by the 50-MHz, clear-air profiler located at White Sands Missile Range, New Mexico. The observations are from radar beams 15 off zenith and extend from about 5 to 20 km altitude. The data are nearly continuous over the 5-year period 1991-1995.

G. D. Nastrom; F. D. Eaton

1997-01-01

324

Spectrum of gamma rays in the 8- to 20MeV range from 252Cf spontaneous fission  

Microsoft Academic Search

The spectrum of gamma rays in the 8- to 20-MeV range has been measured for 252Cf spontaneous fission using a 25.4 cm25.4 cm NaI crystal and time-of-flight separation of gamma rays and neutrons. These data, obtained at three solid angles, are in disagreement with the recent result of Brooks and Reines that gamma-ray events above 10 MeV in their experiment

F. S. Dietrich; J. C. Browne; W. J. O'Connell; M. J. Kay

1974-01-01

325

(H2O)20 Water Clusters at Finite Temperatures  

NASA Astrophysics Data System (ADS)

We have performed an exhaustive study of energetics of (H2O)20 clusters. Our goal is to study the role that various free-energy terms play in this popular model system and see their effects on the distribution of the (H2O)20 clusters and in the infrared spectrum at finite temperatures. In more detail, we have studied the electronic ground-state structure energy and its long-range correlation (dispersion) part, vibrational zero-point corrections, vibrational entropy, and proton configurational entropy. Our results indicate a delicate competition between the energy terms; polyhedral water clusters are destabilized by dispersion interaction, while vibrational terms (zero-point and entropic) together with proton disorder entropy favor them against compact structural motifs, such as the pentagonal edge- or face-sharing prisms. Apart from small water clusters, our results can be used to understand the influence of these energy terms in water/ice systems in general. We have also developed energy expressions as a function of both earlier proposed and novel hydrogen-bond connectivity parameters for prismatic water clusters.

Parkkinen, P.; Riikonen, S.; Halonen, L.

2013-10-01

326

Library managers and information in World 2.0  

Microsoft Academic Search

Purpose The purpose of this paper is to provide library managers with the ability to recognize and address World 2.0 information issues to enhance their ability to develop management plans for the future. Design\\/methodology\\/approach This paper explores what World 2.0 means to library managers in three ways. Three information dimensions are identified using models to examine World 2.0

Suzie Allard

2009-01-01

327

Web 2.0: Conceptual foundations and marketing issues  

Microsoft Academic Search

This paper identifies the technological and commercial foundations of the new category of online applications commonly described as Web 2.0 or Social Media. It examines the relevance of Web 2.0 for Marketing Strategy and for Direct Marketing in particular. The issue is not a clear-cut one: while several observers saw in Web 2.0 a new stage in the evolution of

Efthymios Constantinides; Stefan J. Fountain

2008-01-01

328

Script To Science 2.0 For Scholarly Communication  

Microsoft Academic Search

This article attempts to trace the evolution of scholarly communication from the days of publication of Journal-des-scavans to the era of web 2.0. Explains the Open Access (OA) movement in brief. The views of Harnad (7) on OA are highlighted. The emergence of Open Access 2.0 is put in context. The authors also explain science 2.0 as the emerging practice

Rajendra Babu H; Khaiser Nikam

2009-01-01

329

Evaluating HDR photos using Web 2.0 technology  

NASA Astrophysics Data System (ADS)

High dynamic range (HDR) photography is an emerging technology that has the potential to dramatically enhance the visual quality and realism of digital photos. One of the key technical challenges of HDR photography is displaying HDR photos on conventional devices through tone mapping or dynamic range compression. Although many different tone mapping techniques have been developed in recent years, evaluating tone mapping operators prove to be extremely difficult. Web2.0, social media and crowd-sourcing are emerging Internet technologies which can be harnessed to harvest the brain power of the mass to solve difficult problems in science, engineering and businesses. Paired comparison is used in the scientific study of preferences and attitudes and has been shown to be capable of obtaining an interval-scale ordering of items along a psychometric dimension such as preference or importance. In this paper, we exploit these technologies for evaluating HDR tone mapping algorithms. We have developed a Web2.0 style system that enables Internet users from anywhere to evaluate tone mapped HDR photos at any time. We adopt a simple paired comparison protocol, Internet users are presented a pair of tone mapped images and are simply asked to select the one that they think is better or click a "no difference" button. These user inputs are collected in the web server and analyzed by a rank aggregation algorithm which ranks the tone mapped photos according to the votes they received. We present experimental results which demonstrate that the emerging Internet technologies can be exploited as a new paradigm for evaluating HDR tone mapping algorithms. The advantages of this approach include the potential of collecting large user inputs under a variety of viewing environments rather than limited user participation under controlled laboratory environments thus enabling more robust and reliable quality assessment. We also present data analysis to correlate user generated qualitative indices with quantitative image statistics which may provide useful guidance for developing better tone mapping operators.

Qiu, Guoping; Mei, Yujie; Duan, Jiang

2011-01-01

330

Total detachment cross sections of C-, CH-, C2-, and C2H- incident on N2 at keV energies  

NASA Astrophysics Data System (ADS)

We have measured the total electron detachment cross sections of the negative ions C-, CH-, C2-, and C2H- incident on molecular nitrogen in the velocity range 0.22-0.56 a.u. The data were measured with reliable normalization and, particularly in the critical case of the C- projectile, the absence of beam contamination due to long-lived metastable states. Comparison of all measurements of cross sections with experimental data for other projectiles shows a common velocity dependence with a maximum near 0.4 a.u. This behavior suggests a connection between the anion-N2 electron-loss collision dynamics and that of the shape-resonance process dominant in low-velocity electron-N2 total electron scattering.

Nascimento, R. F.; Mello, S. L. A.; Magnani, B. F.; Sant'Anna, M. M.; Jalbert, Ginette; de Castro Faria, N. V.

2013-06-01

331

Response of 100% internal quantum efficiency silicon photodiodes to 200 eV40 keV electrons  

Microsoft Academic Search

Electron irradiation of 100% internal quantum efficiency silicon photodiodes having a thin (60 ) SiO2 dead layer results in measured responsivities ranging from 0.056 A\\/W at an incident electron energy E0=0.2 keV to 0.24 A\\/W at E0=40 keV. By comparing the data to a Monte Carlo simulation of electron interactions with the photodiode over an energy range of 1-40 keV,

H. O. Funsten; D. M. Suszcynsky; S. M. Ritzau; R. Korde

1997-01-01

332

Interdiffusion in polystyrene crosslinked by keV ion irradiation  

Microsoft Academic Search

Mass transport properties of polymers are deeply influenced by the presence of crosslinks between chains, induced by high-energy ion irradiation. Diffusion coefficients in polystyrene, measured after irradiation with 300-keV protons in the fluence range 10121014 ions\\/cm2, show strong variation up to two orders of magnitude. Diffusion process has been studied in deuterated\\/hydrogenated polystyrene bilayer by using the forward recoil analysis

L. Calcagno; G. Foti

1992-01-01

333

Research 2.0: A Framework for Qualitative and Quantitative Research in Web 2.0 Environments  

Microsoft Academic Search

The paper explores the potential of the Web 2.0 environment for conducting both qualitative and quantitative research. The paper analyzes the emerging Research 2.0 domain using the theoretical framework of Web 2.0 core principles (e.g., web as a platform, harnessing collective intelligence, etc.). These principles, first proposed by Tim O'Reilly, provide a useful lens through which researchers can examine the

Dinesh Rathi; Lisa M. Given

2010-01-01

334

TRACI 2.0: the tool for the reduction and assessment of chemical and other environmental impacts 2.0  

Microsoft Academic Search

TRACI 2.0, the Tool for the Reduction and Assessment of Chemical and other environmental Impacts 2.0, has been expanded and\\u000a developed for sustainability metrics, life cycle impact assessment, industrial ecology, and process design impact assessment\\u000a for developing increasingly sustainable products, processes, facilities, companies, and communities. TRACI 2.0 allows the\\u000a quantification of stressors that have potential effects, including ozone depletion, global

Jane Bare

335

Information Literacy Instruction in the Web 2.0 Library  

ERIC Educational Resources Information Center

|This paper examines how library educators can implement Web 2.0 tools in their Information Literacy programs to better prepare students for the rigors of academic research. Additionally, this paper looks at transliteracy and constructivism as the most useful teaching methods in a Web 2.0 classroom and attempts to pinpoint specific educational

Humrickhouse, Elizabeth

2011-01-01

336

Culture, learning styles, and Web 2.0  

Microsoft Academic Search

This article explores Web 2.0 in interactive learning environments. Specifically, the article examines Web 2.0 as an interactive learning platform that holds potential, but is also limited by learning styles and cultural value preferences. The article explores the issue of control from both teacher and learner perspectives, and in particular the cultural challenges that impact learner control. From the control

Bolanle A. Olaniran

2009-01-01

337

Generation of an OCL 2.0 Parser  

Microsoft Academic Search

The OCL 2.0 specification defines explicitly a concrete and an abstract syntax. The concrete syntax allows modelers to write down OCL expressions in a textual way. The abstract syntax represents the concepts of OCL using a MOF compliant metamodel. OCL 2.0 imple- mentations should follow this specification. In doing so emphasis is placed on the fact that at the end

Birgit Demuth; Heinrich Hussmann; Ansgar Konermann

338

Project WET Curriculum and Activity Guide 2.0  

ERIC Educational Resources Information Center

The "Project WET Curriculum and Activity Guide 2.0" continues Project WET's dedication to 21st-century, cutting-edge water education. Now in full color, Guide 2.0 offers new activities on topics such as National Parks and storm water, fully revised and updated activities from the original Guide and the very best activities gathered from all of

Project WET Foundation, 2011

2011-01-01

339

Unleashing the Power of Web 2.0  

ERIC Educational Resources Information Center

|As Web 2.0 technologies impact the evolution of online learning, they are certain to blur the definitional lines between electronic portfolios and personal learning environments (PLEs). According to Gary Brown, director of Washington State University's Center for Teaching, Learning, and Technology, the Web 2.0 technologies that are emerging

Waters, John K.

2008-01-01

340

Towards Volitional Media Literacy through Web 2.0  

ERIC Educational Resources Information Center

|The authors discuss the results of a study in which they investigated 68 university-level media education students' knowledge of Web 2.0 and their conceptions about its impact on media literacy. The main research finding was that the students argued firmly in favor of new media literacy. Their own use of Web 2.0 applications was, however, rather

Kynaslahti, Heikki; Vesterinen, Olli; Lipponen, Lasse; Vahtivuori-Hanninen, Sanna; Tella, Seppo

2008-01-01

341

Web 2.0 Strategy in Libraries and Information Services  

ERIC Educational Resources Information Center

Web 2.0 challenges libraries to change from their predominantly centralised service models with integrated library management systems at the hub. Implementation of Web 2.0 technologies and the accompanying attitudinal shifts will demand reconceptualisation of the nature of library and information service around a dynamic, ever changing, networked,

Byrne, Alex

2008-01-01

342

Students as Digital Citizens on Web 2.0  

ERIC Educational Resources Information Center

|Internet tools associated with Web 2.0 such as wikis, blogs, and video podcasts are increasingly available in elementary classrooms. ("Web 2.0" is a vaguely defined, folk-tech term that means, roughly, the Internet and all software and devices, constantly improving, that strive to exploit it in creative and useful ways.) Today, elementary

Nebel, Michelle; Jamison, Barbara; Bennett, Linda

2009-01-01

343

Untangling Web 2.0's Influences on Student Learning  

ERIC Educational Resources Information Center

|The recent creation of Web 2.0 applications dramatically alters the ways in which universities recruit and educate students. Technology insiders usually attribute the phrase "Web 2.0" to Tim O'Reilly, author and publisher of the ubiquitous O'Reilly series of technology books (http://oreilly.com). Although there is no shortage of definitions of

Magolda, Peter M.; Platt, Glenn J.

2009-01-01

344

The Next Wave Now: Web 2.0  

ERIC Educational Resources Information Center

|While many people are just getting comfortable with the Internet and e-mail, Web 2.0 technologies are already changing the playing field for education. Though definitions of Web 2.0 vary, the one constant is that Internet users are now content providers rather than content receivers. The top-down approach of the Web has been replaced with users

Mills, Lane B.

2007-01-01

345

WEB 2.0 implications on knowledge management  

Microsoft Academic Search

Purpose - The purpose of this paper is to provide an understanding of the WEB 2.0 phenomenon and its implications on knowledge management; thus, in order to learn whether using WEB 2.0 concepts and tools can yield better assimilation of knowledge management in organizations.

Moria Levy

2009-01-01

346

Metcalfe's law, Web 2.0, and the Semantic Web  

Microsoft Academic Search

The power of the Web is enhanced through the network effect produced as resources link to each other with the value determined by Metcalfe's law. In Web 2.0 applications, much of that effect is delivered through social linkages realized via social networks online. Unfortunately, the associated semantics for Web 2.0 applications, delivered through tagging, is generally minimally hierarchical and sparsely

James A. Hendler; Jennifer Golbeck

2008-01-01

347

The Web 2.0 way of learning with technologies  

Microsoft Academic Search

While there is a lot of hype around various concepts associated with the term Web 2.0 in industry, little academic research has so far been conducted on the implications of these new approaches for the domain of education. Much of what goes by the name of Web 2.0 can in fact be regarded and utilised as a new kind of

Herwig Rollett; Mathias Lux; Markus Strohmaier; Gisela Dsinger; Klaus Tochtermann

2007-01-01

348

The use of Web 2.0 technologies.  

PubMed

Although many publications laud the potential benefits of using Web 2.0 technologies in nursing education, little has been published on the extent of their use. This descriptive study examined the personal and academic use of Web 2.0 technologies among nursing students enrolled in 3 different baccalaureate programs. PMID:22688876

Kohtz, Cindy; Gowda, Connie; Stockert, Patricia; White, Jane; Kennel, Lynn

349

A Framework for Web 2.0 Learning Design  

ERIC Educational Resources Information Center

|This paper describes an approach to conceptualising and performing Web 2.0-enabled learning design. Based on the Technological, Pedagogical and Content Knowledge model of educational practice, the approach conceptualises Web 2.0 learning design by relating Anderson and Krathwohl's Taxonomy of Learning, Teaching and Assessing, and different types

Bower, Matt; Hedberg, John G.; Kuswara, Andreas

2010-01-01

350

Project WET Curriculum and Activity Guide 2.0  

ERIC Educational Resources Information Center

|The "Project WET Curriculum and Activity Guide 2.0" continues Project WET's dedication to 21st-century, cutting-edge water education. Now in full color, Guide 2.0 offers new activities on topics such as National Parks and storm water, fully revised and updated activities from the original Guide and the very best activities gathered from all of

Project WET Foundation, 2011

2011-01-01

351

Scenarios and Strategies for Web 2.0  

ERIC Educational Resources Information Center

|Purpose: The aim of this article is to bring together ideas from the authors' review of the Web 2.0 literature, the data and their insights from this and other technology-related projects to produce a framework for strategies on Web 2.0 focusing on the implications for human resource professionals. Design/methodology/approach: The authors discuss

Martin, Graeme; Reddington, Martin; Kneafsey, Mary Beth; Sloman, Martyn

2009-01-01

352

Culture, Learning Styles, and Web 2.0  

ERIC Educational Resources Information Center

|This article explores Web 2.0 in interactive learning environments. Specifically, the article examines Web 2.0 as an interactive learning platform that holds potential, but is also limited by learning styles and cultural value preferences. The article explores the issue of control from both teacher and learner perspectives, and in particular the

Olaniran, Bolanle A.

2009-01-01

353

Web 2.0: Creating a Classroom without Walls  

ERIC Educational Resources Information Center

|This article is about my year-long journey implementing Web 2.0 tools into my teaching practice. The goal throughout my journey has always been to increase my students' intrinsic motivation to learn about science. The Web 2.0 tools I used along my journey were weblogs (blogs) and podcasts. (Contains 1 figure.)|

Barlow, Tim

2008-01-01

354

Changing Paradigms Managed Learning Environments and Web 2.0  

ERIC Educational Resources Information Center

|Purpose: The purpose of this paper is to understand how emerging technologies and Web 2.0 services are transforming the structure of the web and their potential impact on managed learning environments (MLS) and learning content management systems (LCMS). Design/methodology/approach: Innovative Web 2.0 applications are reviewed in the paper to

Craig, Emory M.

2007-01-01

355

OPAC 2.0: Opportunities, development and analysis. Authors  

Microsoft Academic Search

Web 2.0 has raised new expectations from the library users : after reading a book, they wish to rate it, provide some comments or review about it and tag it for themselves or for others. They also expect to discover other interesting books thanks to the contribution of other people. Those functions, summarized under OPAC 2.0, are now provided by

Patrice CHALON; Emmanuel DI PRETORO; Laurence KOHN

356

Electro-optical climatology microcomputer version 2.0  

Microsoft Academic Search

Electro-optical Climatology (EOCLIMO) Ver 2.0 was developed to enhance employment of precision guided munitions and target acquisition systems. This paper explains how EOCLIMO was produced, and interpretation of each output type. Guidance is provided on EOCLIMO 2.0 program manipulation, station\\/data comparisons, geographical map\\/narrative display, and transmittance versus ceiling output.

Robert L. Miller; Bradley T. Regan

1992-01-01

357

Latitude variation of recurrent MeV-energy proton flux enhancements in the heliocentric radial range 11 t 20 AU and possible correlation with solar coronal hole dynamics  

SciTech Connect

Recurrent low energy (> or approx. =0.5 MeV) proton flux enhancements, reliable indicators of corotating plasma interaction regions in interplanetary space, have been observed on the Voyager 1 and 2 and Pioneer 11 spacecraft in the heliographic latitude range 2/sup 0/S to 23/sup 0/N and the heliocentric radial range 11 to 20 AU. After a period of rather high correlation between fluxes at different latitudes in early 1983, distinct differences develop. The evolution of the fluxes appears to be related to the temporal and latitudinal dynamics of solar coronal holes, suggesting that information about the latitudinal structure of solar wind stream sources propagates to these distances.

Christon, S.P.; Stone, E.C.

1985-02-01

358

Backside-thinned CCDs for keV electron detection  

NASA Astrophysics Data System (ADS)

This paper presents preliminary results on the performance of n-channel, backside-thinned charge-coupled devices (CCDs) as electron-bombarded-semiconductor (EBS) imagers for the detection of 1-10 keV electrons. The devices exhibit average EBS gains ranging from approximately 50 at 1 keV to >1600 at 10 keV. Device radiation tolerance has been investigated by exposing normally-clocked devices to 6 keV electron doses up to 0.01 Coulombs/cm(superscript 2). Room temperature pre- and post-irradiation results are presented for these key device parameters: full well capacity, dark current, and charge transfer efficiency (CTE). At the maximum dose of 0.01 Coulombs/cm(superscript 2), full well capacity decreases 9% from an initial value of 680,000 e(superscript -), and dark current increases from 2) to approximately 50 nA/cm(superscript 2). There are no measurable changes in large signal CTE up to the maximum dose. Radiation damage at energies other than 6 keV is estimated by measurement of the x-ray generation efficiency of silicon as a function of electron energy. Device stability after temperature cycling has been studied by subjecting packaged devices to vacuum bakes of 24 hours at 300 degree(s)C. Full well, CTE, EBS gain, and output amplifier performance are unchanged after the extended temperature cycle, while dark current decreases slightly by 15%. In summary, these initial results indicate that the CCD can function as both an efficient and robust electron imager.

Ravel, Mihir K.; Reinheimer, Alice L.

1991-07-01

359

Single-crystal elastic constants of yttria-stabilized zirconia in the range 20° to 700°C  

Microsoft Academic Search

Elastic constants of single crystals of yttria-stabilized zirconia were determined through the temperature range 20\\/phi\\/ to 700°C. Crystals containing 8.1, 11.1, 12.1, 15.5, and 17.9 mol% YO were measured. The elastic constant C was found to decrease and C and C to increase with increasing YO content; this appears to be due to decreasing coulombic interaction as Y\\/sup 3 +\\/

H. M. Kandil; J. D. Greiner; J. F. Smith

1984-01-01

360

Range predictions for a CO2 laser communication system  

NASA Astrophysics Data System (ADS)

Calculations are presented to permit range predictions of a CO2 laser communication system when attenuation statistics are available. Both TV and digital transmission are considered. In the former case, an AM-FM modulation scheme is used. Direct demodulation is assumed. Examples are given in the use of the results to obtain range probabilities based on reported propagation statistics.

Waksberg, A.

1981-08-01

361

Carbon Cycle 2.0: Ashok Gadgil: global impact  

ScienceCinema

Ashok Gadgil speaks at the Carbon Cycle 2.0 kick-off symposium Feb. 2, 2010. We emit more carbon into the atmosphere than natural processes are able to remove - an imbalance with negative consequences. Carbon Cycle 2.0 is a Berkeley Lab initiative to provide the science needed to restore this balance by integrating the Labs diverse research activities and delivering creative solutions toward a carbon-neutral energy future. http://carboncycle2.lbl.gov/

362

Biofuels Science and Facilities (Carbon Cycle 2.0)  

SciTech Connect

Jay D. Keasling speaks at the Carbon Cycle 2.0 kick-off symposium Feb. 2, 2010. We emit more carbon into the atmosphere than natural processes are able to remove - an imbalance with negative consequences. Carbon Cycle 2.0 is a Berkeley Lab initiative to provide the science needed to restore this balance by integrating the Labs diverse research activities and delivering creative solutions toward a carbon-neutral energy future. http://carboncycle2.lbl.gov/

Keasling, Jay D.

2010-02-04

363

Purification, crystallization and preliminary X-ray diffraction analysis of the IL-20-IL-20R1-IL-20R2 complex  

PubMed Central

Interleukin-20 (IL-20) is an IL-10-family cytokine that regulates innate and adaptive immunity in skin and other tissues. In addition to protecting the host from various external pathogens, dysregulated IL-20 signaling has been shown to contribute to the pathogenesis of human psoriasis. IL-20 signals through two cell-surface receptor heterodimers, IL-20R1IL-20R2 and IL-22R1IL-20R2. In this report, crystals of the IL-20IL-20R1IL-20R2 ternary complex have been grown from polyethylene glycol solutions. The crystals belonged to space group P41212 or P43212, with unit-cell parameters a = 111, c = 135?, and diffracted X-rays to 3? resolution. The crystallographic asymmetric unit contains one IL-20IL-20R1IL-20R2 complex, corresponding to a solvent content of approximately 54%.

Logsdon, Naomi J.; Allen, Christopher E.; Rajashankar, Kanagalaghatta R.; Walter, Mark R.

2012-01-01

364

The Observation of the 3/2(+) State of F-19 at E(X) = 7101 Kev and its Relation to Explosive Stellar Hydrogen Burning  

NASA Astrophysics Data System (ADS)

In extremely hot and dense astrophysical environments, such as in novae events, the energy generation mechanism may shift from cyclic processes involving hydrogen fusion reactions on only low mass (A < 19) nuclei (the HotCNO cycles), to a violent thermonuclear runaway producing heavier mass nuclei up to 68Se and higher (the rp-process). This shift will determine the power output and the timescale of the explosive event and is, thus, clearly important to understand. One of the pathways for this transition to occur is via the 18F(p,/gamma)19Ne reaction which channels material away from the HotCNO cycles to the rp-process. This reaction competes with the 18F(p,?)15O reaction which returns material back to the HotCNO cycles. To determine the temperatures and densities under which such a transition may occur one must know the locations, widths, and spin-parities of resonant states in the compound nucleus 19Ne just above the 18F + p threshold. The purpose of this work was to check on the existence of the astrophysically important 3/2+ resonant state recently reported in 19Ne at E x~ 7.07 MeV, by searching for its isospin mirror state in 19F. This mirror state was, indeed, observed via the 15N(?,?)19F reaction to lie at E x = 7101 1 keV, with alpha width, ??? ? tot = 28 1.1 keV, ?-width, ?gamma = 0.38 0.06 eV, and resonance strength, ?gamma = 0.77 0.11 eV. Under the assumption of equivalent alpha structure of the mirror states, the alpha width of the 19Ne state was determined to be ~30 keV. This is in resonable agreement with two previous studies, but in disagreement, by a factor of ~3, with one. The latest information indicates that the 18F(p,/gamma)19Ne reaction rate under astrophysical conditions is too low for it to be an important pathway for breakout from the HotCNO cycles to the rp-process.

Butt, Yousaf Mahmood

1998-10-01

365

Oh! Web 2.0, Virtual Reference Service 2.0, Tools and Techniques (I): A Basic Approach  

ERIC Educational Resources Information Center

|This study targets librarians and information professionals who use Web 2.0 tools and applications with a view to providing snapshots on how Web 2.0 technologies are used. It also aims to identify values and impact that such tools have exerted on libraries and their services, as well as to detect various issues associated with the implementation

Arya, Harsh Bardhan; Mishra, J. K.

2011-01-01

366

E-Learning practices and Web 2.0  

Microsoft Academic Search

Abstract: In September 2005, more than 2 years ago OReilly published the original definition of the idea of Web 2.0. In the wake of this hype the similar changes in E-Learning have been summarized in the term E-Learning 2.0. This paper aims to give a consolidated review on the development inthese two years; which technologies and trends proved to be

Christian Safran; Denis Helic; Christian Gtl

367

Elevation-Dependent Temperature Trends in the Rocky Mountain Front Range: Changes over a 56- and 20-Year Record  

PubMed Central

Determining the magnitude of climate change patterns across elevational gradients is essential for an improved understanding of broader climate change patterns and for predicting hydrologic and ecosystem changes. We present temperature trends from five long-term weather stations along a 2077-meter elevational transect in the Rocky Mountain Front Range of Colorado, USA. These trends were measured over two time periods: a full 56-year record (19532008) and a shorter 20-year (19892008) record representing a period of widely reported accelerating change. The rate of change of biological indicators, season length and accumulated growing-degree days, were also measured over the 56 and 20-year records. Finally, we compared how well interpolated Parameter-elevation Regression on Independent Slopes Model (PRISM) datasets match the quality controlled and weather data from each station. Our results show that warming signals were strongest at mid-elevations over both temporal scales. Over the 56-year record, most sites show warming occurring largely through increases in maximum temperatures, while the 20-year record documents warming associated with increases in maximum temperatures at lower elevations and increases in minimum temperatures at higher elevations. Recent decades have also shown a shift from warming during springtime to warming in July and November. Warming along the gradient has contributed to increases in growing-degree days, although to differing degrees, over both temporal scales. However, the length of the growing season has remained unchanged. Finally, the actual and the PRISM interpolated yearly rates rarely showed strong correlations and suggest different warming and cooling trends at most sites. Interpretation of climate trends and their seasonal biases in the Rocky Mountain Front Range are dependent on both elevation and the temporal scale of analysis. Given mismatches between interpolated data and the directly measured station data, we caution against an over-reliance on interpolation methods for documenting local patterns of climatic change.

McGuire, Chris R.; Nufio, Cesar R.; Bowers, M. Deane; Guralnick, Robert P.

2012-01-01

368

Characterization of the PILATUS photon-counting pixel detector for X-ray energies from 1.75 keV to 60 keV  

NASA Astrophysics Data System (ADS)

The PILATUS detector module was characterized in the PTB laboratory at BESSY II comparing modules with 320 ?m thick and newly developed 450 ?m and 1000 ?m thick silicon sensors. Measurements were carried out over a wide energy range, in-vacuum from 1.75 keV to 8.8 keV and in air from 8 keV to 60 keV. The quantum efficiency (QE) was measured as a function of energy and the spatial resolution was measured at several photon energies both in terms of the modulation transfer function (MTF) from edge profile measurements and by directly measuring the point spread function (PSF) of a single pixel in a raster scan with a pinhole beam. Independent of the sensor thickness, the measured MTF and PSF come close to those for an ideal pixel detector with the pixel size of the PILATUS detector (172 172 ?m2). The measured QE follows the values predicted by calculation. Thicker sensors significantly enhance the QE of the PILATUS detectors for energies above 10 keV without impairing the spatial resolution and noise-free detection. In-vacuum operation of the PILATUS detector is possible at energies as low as 1.75 keV.

Donath, T.; Brandstetter, S.; Cibik, L.; Commichau, S.; Hofer, P.; Krumrey, M.; Lthi, B.; Marggraf, S.; Mller, P.; Schneebeli, M.; Schulze-Briese, C.; Wernecke, J.

2013-03-01

369

Momentum spectroscopy of fragment ions of a multiply charged N2O molecule under impact of 10-keV electrons  

NASA Astrophysics Data System (ADS)

The dissociative ionization of a N2O molecule is studied at an electron energy of 10 keV using the multiple-ion-coincidence imaging technique. The complete as well as the incomplete Coulomb explosion pathways for N2O2+ and N2O3+ ions are examined and identified. The precursor-specific relative partial ionization cross sections for resulting fragment ions are obtained. It is found that about 81.8% of single ionization, 17.8% of double ionization, and about 0.4% of triple ionization of the parent molecule contribute to the total fragment ion yield. Furthermore, the relative ionic fractions for ion-pair and ion-triple formation are also determined. The kinetic energy release distributions for different coincidence channels are obtained and compared with the available data at lower energies of electron and photon impacts and with that of high-energy ion impact. From the angular correlation studies of fragment ions, it is inferred that states with bent geometries are involved for most of the fragmentation channels of N2O2+ and N2O3+ ions. The concerted and/or sequential nature of the six dissociation pathways is also assigned. No other experimental or theoretical data exist in the literature to compare with the results obtained at the considered impact energy.

Bhatt, Pragya; Singh, Raj; Yadav, Namita; Shanker, R.

2012-11-01

370

20. Historic American Buildings Survey Alex Bush, Photographer, February 2, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

20. Historic American Buildings Survey Alex Bush, Photographer, February 2, 1937 DOOR TO WEST HALL, SECOND FLOOR - East Alabama Masonic Female Institute, 205 East South Street, Talladega, Talladega County, AL

371

DEVSML 2.0: The Language and the Stack.  

National Technical Information Service (NTIS)

This paper presents a revised version of DEVSML stack. The earlier version introduced the concept of transparent simulators in a netcentric domain. This version of DEVSML 2.0 stack introduces the transparent modeling concept and how a platform independent...

S. Mittal S. A. Douglas

2012-01-01

372

1 CFR 20.2 - Preparation of agency statements.  

Code of Federal Regulations, 2012 CFR

...COMMITTEE OF THE FEDERAL REGISTER PREPARATION, TRANSMITTAL, AND PROCESSING OF DOCUMENTS HANDLING OF THE UNITED STATES GOVERNMENT MANUAL STATEMENTS § 20.2 Preparation of agency statements. In accordance with schedules...

2012-01-01

373

Visual Sample Plan Version 2.0 User's Guide.  

National Technical Information Service (NTIS)

This user's guide describes Visual Sample Plan (VSP) Version 2.0 and provides instructions for using the software. VSP selects the appropriate number and location of environmental samples to ensure that the results of statistical tests performed to provid...

N. L. Hassig J. E. Wilson R. O. Gilbert D. K. Carlson R. F. O'Brien B. A. Pulsipher C. A. McKinstry D. J. Bates

2002-01-01

374

Federal Enterprise Architecture Program EA Assessment Framework 2.0.  

National Technical Information Service (NTIS)

Version 2.0 of the Office of Management and Budget (OMB) Enterprise Architecture Assessment Framework is designed to advance the use of enterprise architecture (EA) across the Federal government. This document will serve as the basis for enterprise archit...

2005-01-01

375

50 CFR 20.2 - Relation to other provisions.  

Code of Federal Regulations, 2012 CFR

...WILDLIFE AND PLANTS (CONTINUED) MIGRATORY BIRD HUNTING Introduction § 20.2 Relation to other provisions. (a) Migratory bird permits. The provisions of this part...of this subchapter. (b) Migratory bird hunting stamps. The provisions of...

2012-10-01

376

50 CFR 20.2 - Relation to other provisions.  

Code of Federal Regulations, 2011 CFR

...WILDLIFE AND PLANTS (CONTINUED) MIGRATORY BIRD HUNTING Introduction § 20.2 Relation to other provisions. (a) Migratory bird permits. The provisions of this part...of this subchapter. (b) Migratory bird hunting stamps. The provisions of...

2011-10-01

377

42 CFR 2.20 - Relationship to State laws.  

Code of Federal Regulations, 2012 CFR

...PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL PROVISIONS CONFIDENTIALITY OF ALCOHOL AND DRUG ABUSE PATIENT RECORDS General Provisions § 2.20 Relationship to State laws. The statutes authorizing these...

2012-10-01

378

Finite Range Effects in (alpha, 2alpha) Reactions  

SciTech Connect

Finite range calculations for the (alpha, 2alpha) reactions are performed for the first time to remove huge inconsistencies obtained earlier in conventional zero range analyses. Vagaries of the energy dependent experimental observations up to 200 MeV are understood using the well-established nuclear radii and distorting optical potentials. The results are found to be sensitive to the short distance behavior of the alpha-alpha interaction, indicating the utility of the knockout reactions as a probe of the knockout vertex at short distances. Our approach paves the way to include finite range effects in atomic and molecular physics as also in neutron multiplication calculations.

Jain, Arun K.; Joshi, Bhushan N. [Nuclear Physics Division, Bhabha Atomic Research Center, Mumbai-400 085 (India)

2009-09-25

379

The emerging political economy of Humanity 2.0  

Microsoft Academic Search

Humanity 2.0 refers to the title of my recent book (Humanity 2.0: What It Means to Be Human Past, Present and Future, Palgrave Macmillan, 2011), in which I present humanity as historically poised to re-negotiate its sense of collective identity. There are at least five reasons for this, which are addressed in this paper: (a) the prominence of digital technology

Steve Fuller

2012-01-01

380

The impact of CRM 2.0 on customer insight  

Microsoft Academic Search

Purpose This paper aims to look at what CRM 2.0 is and how it impacts customer insights. It will show how CRM 2.0's incorporation of social tools and strategies with traditional operational functions meets the demands of twenty-first century social customers. Design\\/methodology\\/approach The paper presents a combination of independent research by the author for the last decade and

Paul Greenberg

2010-01-01

381

Web 2.0 Creates a New Government  

Microsoft Academic Search

\\u000a Innovating Government is high on the agenda and has been proven as successful by using Web 2.0. This label includes a new\\u000a wave of web-based applications that rely on the concept of the user as a producer. Web 2.0 provides means to create a better\\u000a Government. As first point, improvements are regarded that are based on providing feedback to agencies.

Roland Traunmller

2010-01-01

382

Security & Privacy Challenges in E-Learning 2.0  

Microsoft Academic Search

E-Learning 2.0 uses Web 2.0 tools for e-learning. New services on the Internet can be swiftly integrated into existing applications; students can create MashUps, for instance, using a variety of services on the Internet. The main risk comes from the fact that students and teachers are not entirely aware that their institution does not control these services. The servers are

Edgar Weippl; Martin Ebner

2008-01-01

383

Changing paradigms: managed learning environments and Web 2.0  

Microsoft Academic Search

Purpose The purpose of this paper is to understand how emerging technologies and Web 2.0 services are transforming the structure of the web and their potential impact on managed learning environments (MLS) and learning content management systems (LCMS). Design\\/methodology\\/approach Innovative Web 2.0 applications are reviewed in the paper to explore how they incorporate a new paradigm, reshaping the

Emory M. Craig

2007-01-01

384

Coming to terms with Web 2.0  

Microsoft Academic Search

Purpose -- This paper aims to discuss Web 2.0 and its web tools.Design\\/methodology\\/approach -- The paper discusses Web 2.0.Findings -- Today there is no single author for many works, often by design, and the proliferation of voices has meant that the traditional print-based criteria previously relied upon have been replaced with a brave new world environment in which anyone

David D. Oberhelman

2007-01-01

385

Databases and Web 2.0 panel at VLDB 2007  

Microsoft Academic Search

Web 2.0 refers to a set of technologies that enables indviduals to create and share content on the Web. The types of content that are shared on Web 2.0 are quite varied and include photos and videos (e.g., Flickr, YouTube), encyclopedic knowledge (e.g., Wikipedia), the blogosphere, social book-marking and even structured data (e.g., Swivel, Many-eyes). One of the important distinguishing

Sihem Amer-yahia; Volker Markl; Alon Y. Halevy; Anhai Doan; Gustavo Alonso; Donald Kossmann; Gerhard Weikum

2008-01-01

386

Telecom mashups: enabling web 2.0 for telecom services  

Microsoft Academic Search

The emerging Web 2.0 marketplace presents an important opportunity for Telecom operators to sell their own capabilities and content as services. Operators have a wealth of content associated with their network as well as core network enablers, e.g. call control, presence and messaging, which could serve as potential new revenue streams in a Web 2.0 world. Moreover, with the looming

Nilanjan Banerjee; Koustuv Dasgupta

2008-01-01

387

SMIL 2.0: XML for Web Multimedia  

Microsoft Academic Search

On 7 August 2001, the World Wide Web Consortium (W3C) released version 2.0 of Synchronized Multimedia Integration Language, or SMIL. Three years ago, SMIL 1.0 introduced a basic foundation for Web multimedia and it quickly gained widespread use. With a specification document about 15 times as large as version 1.0, SMIL 2.0 builds on this foundation and marks an enormous

Lloyd Rutledge

2001-01-01

388

Entrepreneurial marketing and the Web 2.0 interface  

Microsoft Academic Search

Purpose The paper aims to analyse the relationship between marketing and entrepreneurship. It looks at the way in which Web 2.0 technologies are changing the marketing and entrepreneurial landscapes. Design\\/methodology\\/approach The paper explores the impact of Web 2.0 social media for entrepreneurial marketing. It looks at social media as a marketing tool and considers the positive and negative

Brian Jones

2010-01-01

389

Web 2.0 applications in top Chinese university libraries  

Microsoft Academic Search

Purpose This paper aims to explore the status and construction pattern of Web 2.0 technologies employed in top Chinese university libraries, their functionalities and features. Design\\/methodology\\/approach A combination of online survey and content analysis methodology is applied to a sample of 38 top Chinese university libraries' web sites. The Web 2.0 tools are categorized by generally accepted standards

Zhiping Han; Yan Quan Liu

2010-01-01

390

Web 2.0 is cheap: supply exceeds demand  

Microsoft Academic Search

The aim of this paper is to evaluate, from an economic perspective, the efficiency of Web 2.0. It demonstrates that, because of the non?monetary nature of Web 2.0, several sources of inefficiencies (search costs, externalities, crowding out and adverse selection) exist. Nonetheless, the economic nature of digital products and the expected low value of most online content make it impossible

Thierry Rayna; Ludmila Striukova

2010-01-01

391

Media 2.0 - The New Media Revolution?  

Microsoft Academic Search

\\u000a With the rapid development of Web 2.0 and cloud computing concept and applications, there are many unprecedented web-based\\u000a multimedia applications are emerging today and they pose many new challenges in multimedia research. In this talk, I first\\u000a summarize the common features of the new wave of multimedia applications which I call Media 2.0. I use 5 Ds to describe Media

Shipeng Li

2010-01-01

392

Optics upgrades at the APS beamline 20-BM  

NASA Astrophysics Data System (ADS)

Recently, beamline 20-BM has been upgraded with new optics. A large bent cylindrical focusing mirror has been installed to provide an intense focused beam. It is designed to operate over the energy range 2.730 keV, and features a novel Al2O3/Pt coating. When operated near 2.6 mrad, the Pt coating provides good reflectivity up to 30 keV. The Al2O3 overlayer minimizes the influence of the Pt M and L edges. The second upgrade that is in progress is the development of longer KB mirrors. A prototype bender has achieved a focus of about 2.5 ?m using a 300 mm long mirror. Analysis of the focal spot indicates that the size is dominated by the slope errors of the mirror, and can be further reduced if these are minimized by better mirrors or by using differential coating methods.

Heald, Steve M.

2011-09-01

393

NASA Marshall Engineering Thermosphere Model--Version 2.0  

NASA Astrophysics Data System (ADS)

This paper will describe the new NASA Marshall Engineering Thermosphere Model- Version 2.0 (MET-V 2.0) along with an explanation on the use of the computer program plus an example of the MET-V 2.0 model products. The MET-V 2.0 provides an update to the 1988 version of the model. This model provides information on the total mass density, temperature, and individual species number densities for any altitude between 90 and 2500 km as a function of latitude, longitude, time, and solar and geomagnetic activity. A description is given for use of estimated future 13-month smoothed solar flux and geomagnetic index values as input to the model. Using current or past observations of solar radio flux and geomagnetic activity as inputs to the MET-V2.0 model will produce thermospheric density estimates with an accuracy of about 15 percent. However, using future estimates of these input values from generally accepted statistical models (no physical solar model is available for use currently) will result in significantly (order of magnitude effects) reduced accuracy for the calculated thermospheric density values. These are key considerations to the prediction and statistical confidence of satellite orbital lifetimes, orbital insertion altitudes, re-boost requirement, etc for which the MET- V2.0 model (and its predecessors) was developed.

Owens, J.; Vaughan, W.

394

Variable Gap Undulator for 1.5-48 Kev Free Electron Laser at Linac Coherent Light Source  

SciTech Connect

We study the feasibility of generating femtosecond duration Free-Electron Laser with a variable photon energy from 1.5 to 48 keV, using an electron bunch with the same characteristics of the LINAC Coherent Light Source (LCLS) bunch, and a planar undulator with additional focusing. We assume that the electron bunch energy can be changed, and the undulator has a variable gap, allowing a variable undulator parameter. It is assumed to be operated in an ultra-low charge and ultra-short pulse regime. We study the feasibility of a tunable, short pulse, X-ray FEL with photon energy from 1.5 to 48 keV, using an electron beam like the one in the LCLS and a 2:5 cm period, variable gap, planar undulator. The beam energy changes from 4.6 to 13.8 GeV, the electorn charge is kept at 10 pC, and the undulator parameter varies from 1 to 3. The undulator length needed to saturate the 48 keV FEL is about 55 m, with a peak power around 5 GW. At longer wavelength the saturation length is as short as 15 m, and the peak power around 20 GW. The results from the analytical models and the GENESIS simulations show that the system is feasible. The large wavelength range, full tunability and short, few femtosecond pulses, together with the large peak power, would provide a powerful research tool.

Not Available

2011-08-17

395

Effect of 690 keV Xe ion irradiation on the microstructure of amorphous MoSi{sub 2}/SiC nanolayer composites  

SciTech Connect

The effect of 690 keV Xe ion irradiation at three different dosage levels, 1, 5 and 10{times}10{sup 15}/cm{sup 2}, on the microstructure of amorphous-MoSi{sub 2}/amorphous-SiC nanolayer composites has been studied using transmission electron microscopy. Results show that the depth of radiation damage in this multilayer material is {approximately}80 nm, which agrees qualitatively well with the calculated damage depth calculated by TRIM. A diffraction ring corresponding to the (10{bar 1}1) plane of C40 MoSi{sub 2} was found in the electron diffraction pattern taken from the irradiated regions; the C40 phase is also found after thermal annealing of amorphous MoSi{sub 2} at 500{degrees}C or above. In the damaged regions SiC layers were found to spherodize while the nanocrystalline grains in the MoSi{sub 2} layers appeared to coarsen with increasing dose.

Lu, Y.C.; Kung, H.; Jervis, T.R.; Mitchell, T.E.; Nastasi, M. [and others

1996-10-01

396

Low Cost Solar Energy Conversion (Carbon Cycle 2.0)  

SciTech Connect

Ramamoorthy Ramesh from LBNL's Materials Science Division speaks at the Carbon Cycle 2.0 kick-off symposium Feb. 2, 2010. We emit more carbon into the atmosphere than natural processes are able to remove - an imbalance with negative consequences. Carbon Cycle 2.0 is a Berkeley Lab initiative to provide the science needed to restore this balance by integrating the Labs diverse research activities and delivering creative solutions toward a carbon-neutral energy future. http://carboncycle2.lbl.gov/

Ramesh, Ramamoorthy

2010-02-04

397

Crystal structure, short range and long range magnetic ordering in CuSb2O6  

NASA Astrophysics Data System (ADS)

CuSb2O6 crystallizes in a monoclinically distorted trirutile structure. Atomic positions were determined by profile refinement of neutron powder diffraction data, space group P21/n, a = 4.6349(1), b = 4.6370(1), c = 9.2931(1), ? = 91.124(2). Magnetic susceptibility data exhibit a broad maximum at about 60 K and an abrupt transition at 8.5 K. The high temperature data can be fitted to a Curie-Weiss Law giving ?eff = 1.758 and ? = -48 K. Although the crystal structure indicates a nearly square planar Cu2+ lattice as in other trirutiles, a Cu-O-O-Cu superexchange pathway seems to be dominant, giving rise to short range correlations which are approximately one dimensional. The high-temperature susceptibility is explained well by the 1-d Heisenberg model with J/k = -43.1 K. Analysis by Oguchi's method gives a ratio of interchain to intrachain coupling constants of about 2 10-3.

Nakua, A.; Yun, H.; Reimers, J. N.; Greedan, J. E.; Stager, C. V.

1991-03-01

398

Neutron scattering and scaling behavior in URu2Zn20 and YbFe2Zn20  

SciTech Connect

The dynamic susceptibility {chi}*({Delta}E), measured by inelastic neutron-scattering measurements, shows a broad peak centered at E{sub max} = 15 meV for the cubic actinide compound URu{sub 2}Zn{sub 20} and 7 meV at zone center and at the (1/2, 1/2, 1/2) zone boundary for the rare-earth counterpart compound YbFe{sub 2}Zn{sub 20}. For URu{sub 2}Zn{sub 20}, the low-temperature susceptibility and magnetic specific-heat coefficient {gamma} = C{sub mag}/T take the values {chi} = 0.011 emu/mole and {gamma} = 190 mJ/mole K{sup 2} at T = 2 K. These values are roughly three times smaller, and E{sub max} is three times larger, than recently reported for the related compound UCo{sub 2}Zn{sub 20}, so that {chi} and {gamma} scale inversely with the characteristic energy for spin fluctuations, T{sub sf} = E{sub max}/k{sub B}. While {chi}(T), C{sub mag}(T), and E{sub max} of the 4f compound YbFe{sub 2}Zn{sub 20} are very well described by the Kondo impurity model, we show that the model works poorly for URu{sub 2}Zn{sub 20} and UCo{sub 2}Zn{sub 20}, suggesting that the scaling behavior of the actinide compounds arises from spin fluctuations of itinerant 5f electrons.

Wang, C. H. [University of California, Irvine; Christianson, Andrew D [ORNL; Lawrence, J. M. [University of California, Irvine; Bauer, E. D. [Los Alamos National Laboratory (LANL); Goremychkin, E. A. [Argonne National Laboratory (ANL); Kolesnikov, A. I. [Argonne National Laboratory (ANL); Trouw, F. [Los Alamos National Laboratory (LANL); Ronning, F. [Los Alamos National Laboratory (LANL); Thompson, J. D. [Los Alamos National Laboratory (LANL); Lumsden, Mark D [ORNL; Ni, N. [Ames Laboratory and Iowa State University; Mun, E. D. [Ames Laboratory and Iowa State University; Jia, S. [Ames Laboratory and Iowa State University; Canfield, P. C. [Ames Laboratory

2010-01-01

399

A cryogenic electrostatic trap for long-time storage of keV ion beams  

NASA Astrophysics Data System (ADS)

We report on the realization and operation of a fast ion beam trap of the linear electrostatic type employing liquid helium cooling to reach extremely low blackbody radiation temperature and residual gas density and, hence, long storage times of more than 5 min which are unprecedented for keV ion beams. Inside a beam pipe that can be cooled to temperatures <15 K, with 1.8 K reached in some locations, an ion beam pulse can be stored at kinetic energies of 2-20 keV between two electrostatic mirrors. Along with an overview of the cryogenic trap design, we present a measurement of the residual gas density inside the trap resulting in only 2103 cm-3, which for a room temperature environment corresponds to a pressure in the 10-14 mbar range. The device, called the cryogenic trap for fast ion beams, is now being used to investigate molecules and clusters at low temperatures, but has also served as a design prototype for the cryogenic heavy-ion storage ring currently under construction at the Max-Planck Institute for Nuclear Physics.

Lange, M.; Froese, M.; Menk, S.; Varju, J.; Bastert, R.; Blaum, K.; Lpez-Urrutia, J. R. Crespo; Fellenberger, F.; Grieser, M.; von Hahn, R.; Heber, O.; Khnel, K.-U.; Laux, F.; Orlov, D. A.; Rappaport, M. L.; Repnow, R.; Schrter, C. D.; Schwalm, D.; Shornikov, A.; Sieber, T.; Toker, Y.; Ullrich, J.; Wolf, A.; Zajfman, D.

2010-05-01

400

NEUTRON ACTIVATION AT 195 kev  

Microsoft Academic Search

Neutron activation cross sections were measured at 195 kev (50 kev ; energy spread) for about 30 isotopes, bY absolute gamma counting. Absolute ; calibration was effected by determining the RdTh-DO neutron source ; strength with a flat response 4 pi graphite sphere neutron counter, and ; irradiating indium in the form of a thin, uniform, spherical shell. The results

W. S. Lyon; R. L. Macklin

1959-01-01

401

Below 2.0?m CMOS imager technology shrinks  

NASA Astrophysics Data System (ADS)

A quick calculation and accurate estimation algorithm with systematic analysis of optical view is crucial in developing sub 2.0?m imager since as the pixel size scales down below 2.0?m, saturation and sensitivity are reduced more than those expected by nominal scaling factor of CMOS process. In this paper, an unconventional treatment by diffraction focal shift theory is proposed for explaining sub 2.0?m imager shrinks in simple optical language for quick and systematic analyzing the behavior trend of sub 2.0?m imager. Owing to the smaller aperture size (i.e. pixel size), the diffraction focal length is much closer micro lens than geometrical focal length in sub 2.0?m imager. We present the effect of diffraction focal shift on sensitivity spectrum of CMOS imager for 1.7?m with aspect ratio of 2.3 and 1.7. We found that as pixel size shrink, for the sake of imager performance, the aspect ratio should shrink also owing to diffraction focal shift phenomena.

Lee, H. W.; Wu, C. H.

2008-03-01

402

[Surgeon 2.0: the challenge is on the Web].  

PubMed

Numerous articles and opinions have been published in the last few years on how the Internet is changing clinical practice. In this article we focus on describing 2 aspects that we believe are fundamental in the web 2.0 and Medicine-Surgery inter-relationship: a) web 2.0 conceptualisation and its differences with other pre-existing tools, and b) a description of some of the tools that from a medical-surgical view could be of major interest to the professionals, the patients, and interaction between both. The time has arrived to board train 2.0, where the channels of communication between the professionals, and between them and the patients, are improving disease situations daily, to improve learning through contact with other physicians and surgeons, at the same time providing an excellent resource for maintaining health and to know the disease and its treatment. PMID:22658791

Belda Lozano, Ricardo; Ferrer Mrquez, Manuel; Garca Torrecillas, Juan Manuel; Alvarez Garca, Antonio; Reina Duarte, Angel

2012-05-31

403

Geologic Carbon Sequestration and Biosequestration (Carbon Cycle 2.0)  

SciTech Connect

Don DePaolo, Director of LBNL's Earth Sciences Division, speaks at the Carbon Cycle 2.0 kick-off symposium Feb. 3, 2010. We emit more carbon into the atmosphere than natural processes are able to remove - an imbalance with negative consequences. Carbon Cycle 2.0 is a Berkeley Lab initiative to provide the science needed to restore this balance by integrating the Labs diverse research activities and delivering creative solutions toward a carbon-neutral energy future. http://carboncycle2.lbl.gov/

DePaolo, Don (Director, LBNL Earth Sciences Division)

2010-02-03

404

Microsoft Corporation, Sun Microsystems, Microsoft COBOL Version 2.0.  

National Technical Information Service (NTIS)

This Validation Summary Report (VSR) for the Microsoft Corp., Microsoft COBOL Version 2.0 running under the Xenix Version 2.3 provides a consolidated summary of the results obtained from the validation of the subject compiler against the 1974 COBOL Standa...

1984-01-01

405

Incorporating Web 2.0 Technologies from an Organizational Perspective  

NASA Astrophysics Data System (ADS)

The Arctic Research Consortium of the United States (ARCUS) provides support for the organization, facilitation, and dissemination of online educational and scientific materials and information to a wide range of stakeholders. ARCUS is currently weaving the fabric of Web 2.0 technologiesweb development featuring interactive information sharing and user-centered designinto its structure, both as a tool for information management and for educational outreach. The importance of planning, developing, and maintaining a cohesive online platform in order to integrate data storage and dissemination will be discussed in this presentation, as well as some specific open source technologies and tools currently available, including: ? Content Management: Any system set up to manage the content of web sites and services. Drupal is a content management system, built in a modular fashion allowing for a powerful set of features including, but not limited to weblogs, forums, event calendars, polling, and more. ? Faceted Search: Combined with full text indexing, faceted searching allows site visitors to locate information quickly and then provides a set of 'filters' with which to narrow the search results. Apache Solr is a search server with a web-services like API (Application programming interface) that has built in support for faceted searching. ? Semantic Web: The semantic web refers to the ongoing evolution of the World Wide Web as it begins to incorporate semantic components, which aid in processing requests. OpenCalais is a web service that uses natural language processing, along with other methods, in order to extract meaningful 'tags' from your content. This metadata can then be used to connect people, places, and things throughout your website, enriching the surfing experience for the end user. ? Web Widgets: A web widget is a portable 'piece of code' that can be embedded easily into web pages by an end user. Timeline is a widget developed as part of the SIMILE project at MIT (Massachusetts Institute of Technology) for displaying time-based events in a clean, horizontal timeline display. Numerous standards, applications, and 3rd party integration services are also available for use in today's Web 2.0 environment. In addition to a cohesive online platform, the following tools can improve networking, information sharing, and increased scientific and educational collaboration: ? Facebook (Fan pages, social networking, etc) ? Twitter/Twitterfeed (Automatic updates in 3 steps) ? Mobify.me (Mobile web) ? Wimba, Adobe Connect, etc (real time conferencing) Increasingly, the scientific community is being asked to share data and information within and outside disciplines, with K-12 students, and with members of the public and policy-makers. Web 2.0 technologies can easily be set up and utilized to share data and other information to specific audiences in real time, and their simplicity ensures their increasing use by the science community in years to come.

Owens, R.

2009-12-01

406

Nondestructive analysis of phase evolution and microstructure development in Ag/(Bi,Pb)2Sr2Ca2Cu3Ox composite superconductor by 25 keV transmission X-ray diffraction  

NASA Astrophysics Data System (ADS)

X-ray diffraction (XRD) measurements were made on silver-sheathed (Bi,Pb)2Sr2Ca2Cu3Ox (Ag/Bi-2223) composite superconductor using 25 keV X-rays produced by an insertion device beamline at a third generation synchrotron. These measurements, performed on fully sheathed multifilament-type Ag/Bi-2223 wire specimens, provided high resolution diffraction patterns that revealed (1) the phases present in the cores of the superconducting filaments and (2) the nature and quality of the Bi-2223 grain colony texture. In addition to the Bi-2223 phase, we were able to detect and to monitor specimen-to-specimen variations in the relative amounts of Bi-2212, Bi-2201, and the ``3221'' phase. The scattering geometry used (X-ray beam perpendicular to the Ag/Bi-2223 conductor rolling direction) resulted in the detection of several remarkably intense diffraction lines of Bi-2223, most notably the (200)/(020) pair, that were highly useful for recording pole figure maps evidencing the contiguous fiber texture microstructure of the Bi-2223 grain colonies. The nondestructive nature of the 25 keV transmission XRD method offers many advantages for the comprehensive study of phase evolution and microstructure development in Ag/Bi-2223 composite conductors.

Maroni, V. A.; Venkataraman, K.; Kropf, A. J.; Segre, C. U.; Huang, Y.; Riley, G. N.

2002-10-01

407

Formation, structure, and dissociation dynamics of CO2q+ (q?3) ions due to impact of 12-keV electrons  

NASA Astrophysics Data System (ADS)

The electron-impact multiple ionization and subsequent dissociation of CO2 is studied for 12-keV electron energy using a linear time-of-flight mass spectrometer coupled with a multihit, position-sensitive detector. The complete as well as incomplete Coulomb explosion pathways for CO22+ and CO23+ ions are examined and identified. The kinetic energy release distributions for these precursor ions are obtained. The experimental kinetic energy release values for the complete Coulomb fragmentation channels are found to be overestimated by those calculated from the Coulomb explosion model. From the angular correlation studies, it is inferred that bent geometrical states are involved for most of the fragmentation channels of CO22+ and CO23+ ions. The concerted and/or sequential nature of all the dissociation pathways is also assigned. This study provides the first results on energetics associated with the charge separation in dissociative ionization of CO2 under the impact of electrons at a subrelativistic energy.

Bhatt, Pragya; Singh, Raj; Yadav, Namita; Shanker, R.

2012-04-01

408

Verification and validation of DEPOSITION 2.0  

SciTech Connect

The purpose of this document is to verify and validate the usage of the computer program, DEPOSITION 2.0 for use in assessing line loss in CAM and fixed head lines throughout certain Hanford Site facilities. The scope of use is limited to this function. DEPOSITION 2.0 is the second version of this code to be used on the Hanford Site, the program now incorporates additional user-friendly features beyond those which were available in an earlier version, DEPOSITION 1.03.

Eadie, W.J.

1994-10-01

409

Implant 9500xR: a high productivity implantation system for 5E10-1E16 ion.cm-2 dose and 5 keV750 keV energy applications  

Microsoft Academic Search

The capability of the Implant 9500xR ion implanter has been extended to become an all purpose implanter. The Implant 9500xR not only has all capability of a high current implanter, but it can also achieve very stable beam currents well below 1 mA (c.f. medium current implanters) for low dose applications. The ion energy range has also been extended to

B. Adibi; P. Edwards

1996-01-01

410

Investigation of the Equivalence of National Dew-Point Temperature Realizations in the -50 C to + 20 C Range  

NASA Astrophysics Data System (ADS)

In the field of humidity quantities, the first CIPM key comparison, CCT-K6 is at its end. The corresponding European regional key comparison, EUROMET.T-K6, was completed in early 2008, about 4 years after the starting initial measurements in the project. In total, 24 NMIs from different countries took part in the comparison. This number includes 22 EURAMET countries, and Russia and South Africa. The comparison covered the dew-point temperature range from -50 C to +20 C. It was carried out in three parallel loops, each with two chilled mirror hygrometers as transfer standards in each loop. The comparison scheme was designed to ensure high quality results with evenly spread workload for the participants. It is shown that the standard uncertainty due to the long-term instability was smaller than 0.008 C in all loops. The standard uncertainties due to links between the loops were found to be smaller than 0.025 C at -50 C and 0.010 C elsewhere. Conclusions on the equivalence of the dew-point temperature standards are drawn on the basis of calculated bilateral degrees of equivalence and deviations from the EURAMET comparison reference values (ERV). Taking into account 16 different primary dew-point realizations and 8 secondary realizations, the results demonstrate the equivalence of a large number of laboratories at an uncertainty level that is better than achieved in other multilateral comparisons so far in the humidity field.

Heinonen, Martti; Anagnostou, Miltiadis; Bell, Stephanie; Stevens, Mark; Benyon, Robert; Bergerud, Reidun Anita; Bojkovski, Jovan; Bosma, Rien; Nielsen, Jan; Bse, Norbert; Cromwell, Plunkett; Kartal Dogan, Aliye; Aytekin, Seda; Uytun, Ali; Fernicola, Vito; Flakiewicz, Krzysztof; Blanquart, Bertrand; Hudoklin, Domen; Jacobson, Per; Kentved, Anders; Lio, Isabel; Mamontov, George; Masarykova, Alexandra; Mitter, Helmut; Mnguni, Regina; Otych, Jan; Steiner, Anton; Szilgyi Zsfia, Nagyn; Zvizdic, Davor

2012-09-01

411

Mapping ORM 2.0 into OWL 2  

NASA Astrophysics Data System (ADS)

ORM (Object Role Modeling) has been used as an ontology modeling language to model domain ontologies. In order to publish domain ontologies modeled in ORM on the Semantic Web, it needs to translate ORM models into OWL 2, the latest standard Web Ontology Language. Several equivalent transformation methods for ORM model have been considered and a series of mapping rules have been presented.

Pan, Wen-Lin; Liu, Da-Xin

2011-12-01

412

ESTAR, PSTAR, ASTAR: A PC package for calculating stopping powers and ranges of electrons, protons and helium ions, version 2  

Microsoft Academic Search

A PC package is documented for calculating stopping powers and ranges of electrons, protons and helium ions in matter for energies from 1 keV up to 10 GeV. Stopping powers and ranges for electrons can be calculated for any element, compound or mixture. Stopping powers and ranges of protons and helium ions can be calculated for 74 materials (26 elements

M. J. Berger

1993-01-01

413

Carbon Cycle 2.0: Nitash Balsara: Energy Storage  

ScienceCinema

Feb. 4, 2010: Humanity emits more carbon into the atmosphere than natural processes are able to remove - an imbalance with negative consequences. Carbon Cycle 2.0 is a Berkeley Lab initiative to provide the science needed to restore this balance by integrating the Labs diverse research activities and delivering creative solutions toward a carbon-neutral energy future.

414

Carbon Cycle 2.0: Jay Keasling: Biofuels  

ScienceCinema

Feb. 4, 2010: Humanity emits more carbon into the atmosphere than natural processes are able to remove - an imbalance with negative consequences. Carbon Cycle 2.0 is a Berkeley Lab initiative to provide the science needed to restore this balance by integrating the Labs diverse research activities and delivering creative solutions toward a carbon-neutral energy future.

415

Carbon Cycle 2.0: Paul Alivisatos: Solar Fuels  

ScienceCinema

Feb. 4, 2010: Humanity emits more carbon into the atmosphere than natural processes are able to remove - an imbalance with negative consequences. Carbon Cycle 2.0 is a Berkeley Lab initiative to provide the science needed to restore this balance by integrating the Labs diverse research activities and delivering creative solutions toward a carbon-neutral energy future.

416

Web 2.0 Technologies: Applications for Community Colleges  

ERIC Educational Resources Information Center

The current generation of new students, referred to as the Millennial Generation, brings a new set of challenges to the community college. The influx of these technologically sophisticated students, who interact through the social phenomenon of Web 2.0 technology, bring expectations that may reshape institutions of higher learning. This chapter

Bajt, Susanne K.

2011-01-01

417

Social Dimension of Web 2.0 in Engineering Education  

ERIC Educational Resources Information Center

Contemporary engineers need to become more cognizant and more responsive to the emerging needs of the market for engineering and technology services. Social dimension of Web 2.0 which penetrates our society more thoroughly with the availability of broadband services has the potential to contribute decisively to the sustainable development of

Ahrens, Andreas; Zascerinska, Jelena

2010-01-01

418

What, How and Why Web 2.0?  

ERIC Educational Resources Information Center

|This article focuses on introducing Web 2.0 technologies and possible uses for student and teacher learning and collaboration. Many of these tools are already used in social and business contexts. These new and emerging applications are also gaining popularity in classrooms across all education levels. Various applications are introduced to raise

Hanewald, Ria; White, Pennie

2008-01-01

419

MULTIPLE PROJECTIONS SYSTEM (MPS): USER'S MANUAL VERSION 2.0  

EPA Science Inventory

The document is a user's manual for Multiple Projections System (MPS) Version 2.0, based on the 3% reasonable further progress (RFP) tracking system that was developed in FY92/FY93. The 3% RFP tracking system is a Windows application, and enhancements to convert the 3% RFP track...

420

MULTIPLE PROJECTS SYSTEM (MPS) VERSION 2.0 - USER'S MANUAL  

EPA Science Inventory

The document is a user's manual for Multiple Projections System (MPS) Version 2.0, based on the 3% reasonable further progress (RFP) tracking system that was developed in FY92/FY93. he 3% RFP tracking system is a Windows application, and enhancements to convert the 3% RFP trackin...

421

Reality 2.0: When Loss Is Lost  

Microsoft Academic Search

Cyberspace is provoking a dramatic shift in our cultural understanding of reality. A transition is taking place, from a reality marked by loss and limit to one experienced through infinite access. This paper begins to map Reality 2.0 with the conviction that we need to revisit traditional psychoanalytic concepts such as loss and fantasy within the framework of this new

Stephen Hartman

2011-01-01

422

Ethnography 2.0: Writing with Digital Video  

ERIC Educational Resources Information Center

|This article investigates how digital video technology can be used in ethnographic research and considers the implications of digital production, presentation and dissemination of ethnographic educational research knowledge. In this article, I introduce the term Ethnography 2.0 and address some of the issues that emerged from my decision to use

White, M. L.

2009-01-01

423

Learner Digital Stories in a Web 2.0 Age  

ERIC Educational Resources Information Center

|This article reports on a 4-week class project in which students created Web 2.0 digital stories and shared and discussed them with their peers using VoiceThread, a digital media online tool. Participants were English language learners in an academic writing class at a major research university in the United States. Digital stories provided an

Alameen, Ghinwa,

2011-01-01

424

Assessing E-Learning 2.0 System Success  

ERIC Educational Resources Information Center

Traditional e-learning systems support "one-way" communication. Teachers provide knowledge for learners, but they are unable to use a student's learning experiences to benefit the class as a whole. To address these problems, this study explores e-learning success factors via the design and evaluation of an e-learning 2.0 system. This study

Wang, Hei Chia; Chiu, Yi Fang

2011-01-01

425

Key Parameters in Identifying Cost of Spam 2.0  

Microsoft Academic Search

This paper aims to provide an analytical view in estimating the cost of Spam 2.0. For this purpose, the authors define the web spam lifecycle and its associated impact. We also enlisted 5 stakeholders and focused on defining 5 cost calculations using a large collection of references. The cost of web spam then can be calculated with the definition of

Farida Ridzuan; Vidyasagar Potdar; Alex Talevski; William F. Smyth

2010-01-01

426

What Web 2.0 Means for Teachers  

ERIC Educational Resources Information Center

|The term "Web 2.0"--a buzzword for a technological evolution that's been taking place online for some time--has many different definitions. In general, it refers to Web sites that go beyond simply presenting words and images, often allowing users to share information and collaborate in new ways. Content on the Web used to be largely static. One

Criswell, Chad

2008-01-01

427

Student Engagement and Web 2.0: What's the Connection?  

ERIC Educational Resources Information Center

Over the past decade, rising tuition costs and concerns about student success and retention rates have led to an increased focus on levels of student engagement in higher education. The current interest in student engagement may be helping to revive the traditional view of education as a community of learners. The growing use of Web 2.0

Vaughan, Norman

2010-01-01

428

Assessing E-Learning 2.0 System Success  

ERIC Educational Resources Information Center

|Traditional e-learning systems support "one-way" communication. Teachers provide knowledge for learners, but they are unable to use a student's learning experiences to benefit the class as a whole. To address these problems, this study explores e-learning success factors via the design and evaluation of an e-learning 2.0 system. This study

Wang, Hei Chia; Chiu, Yi Fang

2011-01-01

429

Carbon Cycle 2.0: Robert Cheng and Juan Meza  

ScienceCinema

Feb. 4, 2010: Humanity emits more carbon into the atmosphere than natural processes are able to remove - an imbalance with negative consequences. Carbon Cycle 2.0 is a Berkeley Lab initiative to provide the science needed to restore this balance by integrating the Labs diverse research activities and delivering creative solutions toward a carbon-neutral energy future.

430

PRISM 2.0: A Tool for Probabilistic Model Checking  

Microsoft Academic Search

This paper gives a brief overview of version 2.0 of PRISM, a tool for the automatic formal verification of probabilis- tic systems, and some of the case studies to which it has al- ready been applied. The use of probabilistic modelling for the analysis and verification of computer systems is becoming more and more widespread. Probabilistic model checkingis an auto-

Marta Z. Kwiatkowska; Gethin Norman; David Parker

2004-01-01

431

Outcome-Driven Experiential Learning with Web 2.0  

ERIC Educational Resources Information Center

|Experiential learning, an effective pedagogical method in MIS and other business courses, has been limited by instructional formats and teaching resources. But with the advent of Web 2.0 and its rich set of social networking and mass authoring tools, a shift in learning structure in content, process, and outcome is emerging. In this paper, we

Huang, C. Derrick; Behara, Ravi S.

2007-01-01

432

USERS MANUAL: LANDFILL GAS EMISSIONS MODEL - VERSION 2.0  

EPA Science Inventory

The document is a user's guide for a computer model, Version 2.0 of the Landfill Gas Emissions Model (LandGEM), for estimating air pollution emissions from municipal solid waste (MSW) landfills. The model can be used to estimate emission rates for methane, carbon dioxide, nonmet...

433

Journalism Students, Web 2.0 and the Digital Divide  

ERIC Educational Resources Information Center

|The purpose of this study was to find out if students were utilizing Web 2.0 applications. Since the applications in question are often employed by the media industry, the study aspired to find out if students majoring in mass communication and journalism utilized the applications more often than other students. The "digital divide" is a term

Green, Mary Elizabeth

2009-01-01

434

Emergent Learning and Learning Ecologies in Web 2.0  

ERIC Educational Resources Information Center

This paper describes emergent learning and situates it within learning networks and systems and the broader learning ecology of Web 2.0. It describes the nature of emergence and emergent learning and the conditions that enable emergent, self-organised learning to occur and to flourish. Specifically, it explores whether emergent learning can be

Williams, Roy; Karousou, Regina; Mackness, Jenny

2011-01-01

435

Student Engagement and Web 2.0: What's the Connection?  

ERIC Educational Resources Information Center

|Over the past decade, rising tuition costs and concerns about student success and retention rates have led to an increased focus on levels of student engagement in higher education. The current interest in student engagement may be helping to revive the traditional view of education as a community of learners. The growing use of Web 2.0

Vaughan, Norman

2010-01-01

436

ONLINE SOCIAL COMPARISON: IMPLICATIONS DERIVED FROM WEB 2.0  

Microsoft Academic Search

Online purchase has become a mainstream channel for modern consumers to acquire goods and services. With the emergence of Web 2.0, consumers are now able to view and exchange product information with trusted friends instead of strangers. The result is that the effects of social comparison can be naturally created while consumers communicate with their friends online. However, while the

Ling-Ling Wu; Lynne Lee

2008-01-01

437

2.0 at AASL 2009 National Conference in Charlotte  

ERIC Educational Resources Information Center

School library media specialists are information and communication specialists who lead and model these roles in schools and at their major professional events making use of the relevant new Web 2.0 tools available to them to network, collaborate, and share. Using these tools effectively helps them become leaders in their buildings and districts.

Valenza, Joyce Kasman

2009-01-01

438

Teaching Talented Writers with Web 2.0 Tools  

ERIC Educational Resources Information Center

This article is a review of 12 online writing resources and contains suggestions about how such resources might be used in a differentiated classroom with talented writers. Youth with writing talent are defined by distinguishing characteristics and the authors discuss how those characteristics can be supported and enhanced using Web 2.0 tools.

Olthouse, Jill M.; Miller, Myriah Tasker

2012-01-01

439

Conceptualising Teachers' Professional Learning with Web 2.0  

ERIC Educational Resources Information Center

Purpose: This paper seeks to identify and develop an exploratory framework for conceptualising how teachers might use the affordances of Web 2.0 technologies to support their own professional learning. Design/methodology/approach: The paper draws on a large corpus of literature and recent research evidence to identify the principal elements and

Burden, Kevin John

2010-01-01

440

Specifying Quality Requirements for the Web 2.0 Applications  

Microsoft Academic Search

To specify quality requirements for Web 2.0 applications we propose an integrated approach which considers features for contents, functionalities and services. In this work we discuss how to model internal quality, external quality and quality in use views taking into account not only the software characteristics - as those specified in the ISO 9126-1 quality models- but also the own

Luis Olsina; Roberto Sassano; Luisa Mich

2008-01-01

441

Conceptualising Teachers' Professional Learning with Web 2.0  

ERIC Educational Resources Information Center

|Purpose: This paper seeks to identify and develop an exploratory framework for conceptualising how teachers might use the affordances of Web 2.0 technologies to support their own professional learning. Design/methodology/approach: The paper draws on a large corpus of literature and recent research evidence to identify the principal elements and

Burden, Kevin John

2010-01-01

442

Problem-Based Learning via Web 2.0 Technologies  

Microsoft Academic Search

During the last few decades, medical education is shifting is increasingly embracing active learning approaches. This shift from teaching to learning is also strongly related to an involvement of information and communication technology, and especially the Internet and the Web. The emergence of Internet 2.0 is indeed being stressed as a promising tool for advanced support of medicine and medical

Eleni Kaldoudi; Panagiotis D. Bamidis; Miltiadis Papaioakeim; Vassilis Vargemezis

2008-01-01

443

Web 2.0: hypertext by any other name?  

Microsoft Academic Search

Web 2.0 is the popular name of a new generation of Web applications, sites and companies that emphasis openness, community and interaction. Examples include technologies such as Blogs and Wikis, and sites such as Flickr. In this paper we compare these next generation tools to the aspirations of the early Hypertext pioneers to see if their aims have finally been

David E. Millard; Martin Ross

2006-01-01

444

Teaching Talented Writers with Web 2.0 Tools  

ERIC Educational Resources Information Center

|This article is a review of 12 online writing resources and contains suggestions about how such resources might be used in a differentiated classroom with talented writers. Youth with writing talent are defined by distinguishing characteristics and the authors discuss how those characteristics can be supported and enhanced using Web 2.0 tools.

Olthouse, Jill M.; Miller, Myriah Tasker

2012-01-01

445

Experience of Integrating Web 2.0 Technologies  

ERIC Educational Resources Information Center

|Web users in the 21st century are no longer only passive consumers. On a contrary, they are active contributors willing to obtain, share and evolve information. In this paper we report our experience regarding the implementation of Web 2.0 concept in several Computer Ethics related courses jointly conducted at two Universities. These courses have

Zdravkova, Katerina; Ivanovic, Mirjana; Putnik, Zoran

2012-01-01

446

Web 2.0 and Emerging Technologies in Online Learning  

ERIC Educational Resources Information Center

|As online learning continues to grow, so do the free or nearly free Web 2.0 and emerging online learning technologies available to faculty and students. This chapter explores the implementation process and corresponding considerations of adapting such tools for teaching and learning. Issues addressed include copyright, intellectual property,

Diaz, Veronica

2010-01-01

447

MSR 2.0: Language Definition and Programming Environment.  

National Technical Information Service (NTIS)

This report defines the syntax and semantics of the specification language MSR 2.0, and gives requirements for a run-time environment for it. Specifically, it defines the concrete syntax of the language and formalizes its typing and execution semantics at...

I. Cervesato

2011-01-01

448

Technology Help 2.0: Solutions for the Information Commons  

Microsoft Academic Search

Access services librarians at Southeastern Louisiana University's Sims Memorial Library observed patrons' technology help needs and created an interactive training manual that empowers library faculty and staff to provide public service technology help in the Information Commons. The new training manual takes technology help in the academic library to the next level, Technology Help 2.0, because it allows librarians to

Kathryn W. Munson

2008-01-01

449

Bewertung der Informationsqualitt im Enterprise 2.0  

NASA Astrophysics Data System (ADS)

Die Entwicklungen zum Web 2.0 haben das World Wide Web (WWW) grundlegend verndert. Nachdem die meisten Nutzer im WWW zunchst "nur" nach Informationen suchten stellen Nutzer inzwischen sehr ausgiebig Informationen ber sich selbst oder ihnen vertraute Themen in Blogs und Communities bereit. Facebook und Wikipedia sind zwei prominente Webseiten. Ihre Attraktivitt entstammt allein den Informationen, welche die Nutzer selber zur Verfgung stellen.

Ahlheid, Sven; Graefe, Gernot; Krebs, Alexander; Schuster, Dirk

450

Librarians 2.0: Sowing Padi in (the) SEA  

ERIC Educational Resources Information Center

|Purpose: The purpose of this paper is to present an exploratory survey as part of a presentation for the Bridging Worlds 2008 conference. It seeks to understand how library institutions in the South East Asia (SEA) region have implemented Web 2.0 technologies--blogs, RSS feeds, wikis, or the use of services like Flickr, YouTube, de.lici.ous.

Chew, Ivan

2009-01-01

451

Integrating Web 2.0 across the Curriculum  

ERIC Educational Resources Information Center

|For many years, educators have touted the benefits of learning with educational tools such as spreadsheets and databases that allow students to actively process and manipulate information (Jonassen, 1995). Hundreds if not thousands of Web 2.0 tools have been created in the last few years, taking the "technology as tool" metaphor to a new level.

Oliver, Kevin

2010-01-01

452

Web 2.0 Technologies: Applications for Community Colleges  

ERIC Educational Resources Information Center

|The current generation of new students, referred to as the Millennial Generation, brings a new set of challenges to the community college. The influx of these technologically sophisticated students, who interact through the social phenomenon of Web 2.0 technology, bring expectations that may reshape institutions of higher learning. This chapter

Bajt, Susanne K.

2011-01-01

453

Teaching web development in the web 2.0 era  

Microsoft Academic Search

We are experiencing a qualitatively different era of the Web, as evidenced by most Web applications and websites that have emerged and transpired over recent years. The new Web 2.0 era and the technologies beneath it provide both demands and challenges for IT educators to reform traditional Web Development courses. This paper presents our shared experiences and knowledge in teaching

Ye Diana Wang; Nima Zahadat

2009-01-01

454

Web 2.0 in teaching-learning multiculturalism  

Microsoft Academic Search

As the use of technology becomes widespread, more and more advancements are being created to enable people to participate interactively in many global societies. Web 2.0 is a new technology that has tremendous possibilities for social collaboration. Multicultural education has huge potential to help in the fight against racism, and to enable people to become active members of a democratic

M. M. Hossain; H. Aydin

2010-01-01

455

Medical Informatics in the Web 2.0 Era  

Microsoft Academic Search

The main role of medical and healthcare informatics is the manipulation of medical information and the dissemination of knowledge. The advent of the Web increased the pervasiveness of medical information and attracted the interest of both practitioners and patients. Web 2.0 in its turn brings people together in a more dynamic, interactive space. With new services, applications and devices, it

Iraklis Varlamis; Ioannis Apostolakis

2008-01-01

456

Carbon Cycle 2.0: Berend Smit: Carbon Capture  

ScienceCinema

Feb. 3, 2010: Humanity emits more carbon into the atmosphere than natural processes are able to remove - an imbalance with negative consequences. Carbon Cycle 2.0 is a Berkeley Lab initiative to provide the science needed to restore this balance by integrating the Labs diverse research activities and delivering creative solutions toward a carbon-neutral energy future.

457

Swift Galactic Plane Survey: Sourcelist v2.0  

NASA Astrophysics Data System (ADS)

The Swift Galactic Plane Survey team report the detection of 271 point-like X-ray sources (0.3 - 10 keV) in observations covering the next 35% of our survey area (now 60% complete; the first increment of sources, 140 detections in the first 25% of the survey area, may be found in Atel #3951). The listed sources are those we consider to be robust detections at the current time. Further source releases will occur as observations are accumulated.

Reynolds, M. T.; Miller, J. M.; Maitra, D.; Gultekin, K.; Gehrels, N.; Kennea, J.; Siegel, M.; Gelbord, J.; Kuin, P.

2012-08-01

458

The (3He, tf) as a surrogate reaction to determine (n, f) cross sections in the 10-20 MeV energy range  

NASA Astrophysics Data System (ADS)

The surrogate reaction 238U(3He, tf) is used to determine the 237Np(n, f) cross section indirectly over an equivalent neutron energy range from 10 to 20 MeV. A self-supporting 761 ?g/cm2 metallic 238U foil was bombarded with a 42 MeV 3He2+ beam from the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory (LBNL). Outgoing charged particles and fission fragments were identified using the Silicon Telescope Array for Reaction Studies (STARS) consisted of two 140 ?m and one 1000 ?m Micron S2 type silicon detectors. The 237Np(n, f) cross sections, determined indirectly, were compared with the 237Np(n, f) cross section data from direct measurements, the Evaluated Nuclear Data File (ENDF/B-VII.0), and the Japanese Evaluated Nuclear Data Library (JENDL 3.3) and found to closely follow those datasets. Use of the (3He, tf) reaction as a surrogate to extract (n, f) cross sections in the 10-20 MeV equivalent neutron energy range is found to be suitable.

Basunia, M. S.; Clark, R. M.; Goldblum, B. L.; Bernstein, L. A.; Phair, L.; Burke, J. T.; Beausang, C. W.; Bleuel, D. L.; Darakchieva, B.; Dietrich, F. S.; Evtimova, M.; Fallon, P.; Gibelin, J.; Hatarik, R.; Jewett, C. C.; Lesher, S. R.; McMahan, M. A.; Rodriguez-Vieitez, E.; Wiedeking, M.

2009-06-01

459

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

PubMed Central

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

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

2013-01-01

460

Learning about Learning 2.0: Evaluating the "New South Wales Public Library Learning 2.0" Program  

ERIC Educational Resources Information Center

The "New South Wales Learning 2.0" training program is being made available to the entire NSW public library work force of over 2300 people in 2008-2009. This paper is a snapshot of the impact of the course as at September 2008, five months after it was launched. It explores how the training impacted on the staff skill levels, knowledge, and

Forsyth, Ellen; Joseph, Mylee; Perry, Leanne

2009-01-01

461

Dielectric study of allyl chloride with 2-butanol in microwave frequency range  

NASA Astrophysics Data System (ADS)

Dielectric measurement on binary mixtures of Allyl chloride (AC) with 2-butanol have been carried out over the entire concentration range using Time Domain Reflectometry (TDR) technique at 283.15K in the microwave frequency range of 10 MHz to 20 GHz. The static dielectric constant, relaxation time, density, excess static dielectric constant, excess inverse relaxation time, Bruggeman factor, excess molar volume of binary mixtures over entire concentration range were determined to explore the effect hetero molecular interaction. Excess parameters are fitted to Redlich-Kister equation.

Maharolkar, A. P.; Sudake, Y. S.; Kamble, S. P.; Murugkar, A. G.; Patil, S. S.; Khirade, P. W.

2013-06-01

462

Single-Electron Capture into Ar + Excited States in Ar + Na Collision Below 12 Kev. 2: Relative Population Distributed in Ar + Excited States.  

National Technical Information Service (NTIS)

Excitation cross-sections are obtained for each term of the ArII nl-states (nl=4p, 4p' and 4d) at 4 and 8 keV. The relative population distribution among the terms of a given nl-state can be interpreted in terms of statistics based on the building-up prin...

A. Matsumoto S. Tsurubuchi K. Okuno S. Ohtani T. Iwai

1979-01-01

463

Photoresponse in the visible range from Cr doped TiO2 nanotubes  

Microsoft Academic Search

Layers of TiO2 nanotubes have been fabricated by electrochemical anodization of Ti. After annealing the tubes to an anatase structure Cr doping was carried out by ion implantation at an energy of 60 keV and at two nominal fluences, 5 1015 cm-2 and 5 1016 cm-2. XRD measurements reveal that the anatase structure shows a certain degree of

Andrei Ghicov; Bernd Schmidt; Julia Kunze; Patrik Schmuki

2007-01-01

464

AFCI-2.0 Library of Neutron Cross Section Covariances  

SciTech Connect

Neutron cross section covariance library has been under development by BNL-LANL collaborative effort over the last three years. The primary purpose of the library is to provide covariances for the Advanced Fuel Cycle Initiative (AFCI) data adjustment project, which is focusing on the needs of fast advanced burner reactors. The covariances refer to central values given in the 2006 release of the U.S. neutron evaluated library ENDF/B-VII. The preliminary version (AFCI-2.0beta) has been completed in October 2010 and made available to the users for comments. In the final 2.0 release, covariances for a few materials were updated, in particular new LANL evaluations for {sup 238,240}Pu and {sup 241}Am were adopted. BNL was responsible for covariances for structural materials and fission products, management of the library and coordination of the work, while LANL was in charge of covariances for light nuclei and for actinides.

Herman, M.; Herman,M.; Oblozinsky,P.; Mattoon,C.; Pigni,M.; Hoblit,S.; Mughabghab,S.F.; Sonzogni,A.; Talou,P.; Chadwick,M.B.; Hale.G.M.; Kahler,A.C.; Kawano,T.; Little,R.C.; Young,P.G.

2011-06-26

465

Knowledge Management System Based on Web 2.0 Technologies  

NASA Astrophysics Data System (ADS)

Most of the research work on knowledge management systems has been addressed to knowledge representation, storage, and retrieval. However, user interaction has suffered from the same limitations faced by most current Web-based systems. Web 2.0 technologies bring completely new elements that make possible designing user interfaces similar to those that could be built in windowing environments of current desktop platforms. These technologies open new possibilities to enhance user experience when working with Web-based applications. This chapter shows how Web 2.0 technologies could be used to design user interaction in a knowledge management system. Details presented could be useful to improve online interaction with Web-based support systems (WSS) in other application domains.

Jimenez, Guillermo; Barradas, Carlos

466

Engineer's Refractive Effects Prediction System (EREPS), revision 2.0  

NASA Astrophysics Data System (ADS)

The Engineer's Refractive Effects Prediction System (EREPS) is a system of individual stand-alone IBM/PC-compatible programs that have been designed to assist an engineer in properly assessing electromagnetic propagation effects of the lower atmosphere on proposed radar, electronic warfare, or communication systems. The EREPS models account for effects from optical interference, diffraction, tropospheric scatter, refraction, evaporation and surface-based ducting, and water-vapor absorption under horizontally homogeneous atmospheric conditions. EREPS revision 2.0 is an upgrade to revision 1.0 released in July 1988 (Hitney, 1988). There are two completely new programs in revision 2.0, COVER and PROPH, and a user-callable propagation-factor source code subroutine that may be helpful to anyone who wants to integrate the EREPS propagation model into their own applications program.

Patterson, W. L.; Hattan, C. P.; Hitney, H. V.; Paulus, R. A.; Barrios, A. E.; Lindem, G. E.; Anderson, K. D.

1990-02-01

467

Ferroquadrupolar ordering in PrTi2Al20  

NASA Astrophysics Data System (ADS)

The origin of the nonmagnetic phase transition in PrTi2Al20, reported earlier in a macroscopic study, has been asserted microscopically using elastic and inelastic neutron scattering techniques. It has been shown spectroscopically that the crystalline-electric-field ground state is a nonmagnetic ?3 doublet, whereas the excited states are two triplets (?4 and ?5) and a singlet (?1). The diffraction experiment under external magnetic field shows that the nonmagnetic transition is indeed ferroquadrupolar ordering, which takes place as a consequence of cooperative removal of the ground-state-doublet degeneracy. It is therefore concluded that PrTi2Al20 is another rare example of Pr compounds exhibiting nonmagnetic quadrupolar order.

Sato, Taku J.; Ibuka, Soshi; Nambu, Yusuke; Yamazaki, Teruo; Hong, Tao; Sakai, Akito; Nakatsuji, Satoru

2012-11-01

468

Scintillation Response of CaF2 to H and He over a Continuous Energy Range  

SciTech Connect

Recent demands for new radiation detector materials with improved ?-ray detection performance at room temperature have prompted research efforts on both accelerated material discovery and efficient techniques that can be used to identify material properties relevant to detector performance. New material discovery has been limited due to the difficulties of large crystal growth to completely absorb ??energies; whereas high-quality thin films or small crystals of candidate materials can be readily produced by various modern growth techniques. In this work, an ion-scintillator technique is demonstrated that can be applied to study scintillation properties of thin films and small crystals. The scintillation response of a benchmark scintillator, europium-doped calcium fluoride (CaF2:Eu), to energetic proton and helium ions is studied using the ion-scintillator approach based on a time of flight (TOF) telescope. Excellent energy resolution and fast response of the TOF telescope allow quantitative measurement of light yield, nonlinearity and energy resolution over an energy range from a few tens to a few thousands of keV.

Zhang, Yanwen; Xiang, Xia; Weber, William J.

2008-06-07

469

Web2.0 Tools to Support the Instructional Method \\  

Microsoft Academic Search

This research aims at improving the instructional method ldquoThinking actively in a creative environmentrdquo TACE with Web2.0 based tools. These tools we have developed enable the participation of many people in idea generation and evaluation sessions forming brainstorming networks. They also allow the formation of innovation development teams based on the affinity among the participants for their creativity and their

Oscar Ardaiz-villanueva; Xabier Nicuesa Chacn; Oscar Brene Artazcoz; Mara Luisa Sanz De Acedo Lizarraga; Mara Teresa Sanz De Acedo Baquedano

2009-01-01

470

Business Unusual: Corporate Responsibility in a 2.0 World  

Microsoft Academic Search

The imperatives of a growing consensus on human?induced causes of climate change, an increasing gap between rich and poor, and the misguided incentives in the economic, business, and financial models that dominated the last quarter of the twentieth century and first decade of the twenty?first century along with the emergence of Web 2.0's transparency have highlighted the need for a

SANDRA WADDOCK; MALCOLM MCINTOSH

2011-01-01

471

Business Unusual: Corporate Responsibility in a 2.0 World  

Microsoft Academic Search

ABSTRACTThe imperatives of a growing consensus on human?induced causes of climate change, an increasing gap between rich and poor, and the misguided incentives in the economic, business, and financial models that dominated the last quarter of the twentieth century and first decade of the twenty?first century along with the emergence of Web 2.0's transparency have highlighted the need for a

SANDRA WADDOCK; MALCOLM MCINTOSH

472

Traitors Collaborating in Public: Pirates 2.0  

Microsoft Academic Search

This work introduces a new concept of attack against traitor tracing schemes. We call attacks of this type Pirates2.0 attacks\\u000a as they result from traitors collaborating together in a public way. In other words, traitors do not secretly collude but display part of their secret keys in a public place; pirate decoders\\u000a are then built from this public information. The

Olivier Billet; Duong Hieu Phan

2009-01-01

473

Nonmetal-metal transition in Znn (n=2 20) clusters  

Microsoft Academic Search

By using density functional calculation with generalized gradient approximation, we have studied the structural and electronic properties of the zinc clusters. The lowest-energy structures of Znn (n=2 20) clusters are determined. Three kinds of growth pathways are obtained in the small zinc clusters from Zn4 to Zn8 and tetrahedron-based structures have favorable energy. The zinc clusters with 7 16 atoms

Jinlan Wang; Guanghou Wang; Jijun Zhao

2003-01-01

474

Supporting Productive Integration of Web 2.0-Mediated Collaboration  

Microsoft Academic Search

\\u000a This paper describes a research evidence-based practice model, TSOI Hybrid Learning Model as a viable alternative to support\\u000a productive integration of Web 2.0-mediated collaboration for learning. The model is advanced from the Science learning cycle\\u000a and the Kolbs experiential learning cycle. An authentic example on understanding multimedia learning pedagogy for pre-service\\u000a teachers in chemistry education is illustrated. The model guides

Mun Fie Tsoi; Nanyang Walk

475

Different aspects of a relation: radio pulsation and zebra pattern in the broad frequency range 20-7000 MHz  

NASA Astrophysics Data System (ADS)

Zebra- structure (ZS) in the continuous emission of type IV solar radio bursts is frequently observed simultaneously with the second pulsations. In the meter wave band pulsations resemble greatly periodic type III radio bursts against the background of flare continuum, after type II radio burst. In this case fast electrons, responsible for ZS, can be connected only indirectly with the electrons, responsible for type III bursts, when particles can be trapped, for example, between the shock front and the forward edge of CME. In the decimeter range ZS is more frequently observed in the LF part of the spectrum of pulsations, when the same particles can be captured into the magnetic trap, at the top of which the conditions for the excitation of ZS realize. In cm wave band ZS appears frequently against the background of pulsations in any part of the spectrum. This testifies about the fact that the same rapid particles are responsible for both types of fine structure, and the excitation of ZS is connected with the deformation of the distribution function as a result of the quasi-linear diffusion of generated waves on fast particles. Observations of ZS are usually limited from the high frequencies (near 5500 MHz) due to bremsstrahlung absorption of the upper-hybrid plasma waves emission in the background plasma. In the event April 21, 2002 about 35 stripes of ZS of almost identical intensity were observed in the range 2,6-3,8 MHz with a hardly noticeable increase in the frequency separation with frequency. This large number of stripes is difficult to match with the emission mechanism at the double plasma resonance from a distributed radio source but it is possible to reconcile with the new mechanism of a trapping of Z- mode in density enhancements and the emission at eigenfrequencies from a point source by analogy with the mechanism of the auroral roar emission in the terrestrial ionosphere (LaBelle, Treumann, Yoon, Karlicky, 2003, Ap. J., 593, 1195).

Chernov, G. P.; Yan, Y.; Fu, Q.

476

The INTEGRAL View Of The 511 keV Annihilation Line In Our Galaxy  

NASA Astrophysics Data System (ADS)

It is well know from theory and laboratory practice that an electron-positron pair can annihilate into a couple of 511 keV (the electron rest mass) gamma ray photons. The first detection of 511 keV photons from the Galactic center region dates back to early seventies. Soon after, a continuum gamma ray emission due to 3 gamma ortho-positronium decay was also measured. A 511 keV line in the Galactic gamma ray emission gives a unique proof that a large number of positrons are injected in the astrophysical environments, but nowadays we still do not know where these particles are generated. Positrons can be generated by a number of processes, in particular beta+ decays of unstable isotopes produced by stars and supernovae and energetic outflows from compact objects, but the few claimed detections of a 511 keV line from compact galactic sources are quite controversial. This fact could be explained by propagation of positrons in the intergalactic medium before they annihilate away from the birth place. The measure made with the spectrometer SPI aboard INTernational Gamma RAy Laboratory (INTEGRAL), launched on October 17 2002, confirms that about 10E43 positrons per second annihilate in the bulge of our Galaxy. Moreover, there is some evidence of an asymmetry of the 511 keV emission along the Galactic longitude, possibly correlated with the spacial distribution of the hard X (E > 20 keV) Low Mass X-ray Binaries detected by the imager IBIS aboard INTEGRAL. With IBIS, using about 5 years of observations, we find no evidence of 511 keV point sources. With an exposure of 10 Ms, in the center of the Galaxy we estimate a 1.6 x 10E-04 ph/cm2/s flux 2 sigma upper limit; a similar limit is given in a wide area in the Galactic center region with similar exposures.

De Cesare, G.

2011-09-01

477

Thin disk laser in the 2?m wavelength range  

NASA Astrophysics Data System (ADS)

The thin disk laser is a successful concept for high output power and/or high pulse energy, high efficiency and good beam quality in the 1 ?m range. Holmium-doped materials are a promising approach to transform this success to the 2 ?m range. Ho:YAG is especially interesting for high pulse energies due to the long fluorescence lifetime (~ 8 ms) which provides good energy storage capabilities. We have realized a Ho:YAG thin-disk laser with a cw output power of 15 W at 2.09 ?m and a maximum optical-to-optical efficiency of 37%. The laser was pumped with a Tm-fiber laser. Numerical simulations of the Ho:YAG thin disk laser show the potential for further scaling. As broadly tunable alternative, also a Cr:ZnSe thin disk laser was investigated. A Tm-fiber laser and a fiber coupled diode stack were tested as pump sources. A laser power of 3.5 W was achieved with diode pumping.

Speiser, Jochen; Renz, Gnther; Giesen, Adolf

2012-11-01

478

Measurements of keV neutron capture cross sections with a 4. pi. barium fluoride detector: Examples of sup 93 Nb, sup 103 Rh, and sup 181 Ta  

SciTech Connect

A new experimental method has been implemented for precise measurements of neutron capture cross sections in the energy range from 3 to 200 keV. Neutrons are produced via the {sup 7}Li({ital p},{ital n}){sup 7}Be reaction using a pulsed 3-MV Van de Graaff accelerator. The neutron energy is determined by the time-of-flight (TOF) technique using flight paths of less than 1 m. Capture events are detected with a 4{pi} barium fluoride detector. This detector is characterized by a resolution in gamma-ray energy of 14% at 662 keV and 7% at 2.5 MeV, a time resolution of 500 ps, and a peak efficiency of 90% at 1 MeV. Capture events are registered with {similar to}95% probability above a gamma-ray threshold of 2.5 MeV. The combined effect of the relatively short primary flight path, the 10-cm inner radius of the detector sphere, and of the low capture cross section of BaF{sub 2} shifts the background due to capture of sample scattered neutrons in the scintillator to later TOF and therefore leaves the high-energy portion of the TOF spectrum undisturbed. The high efficiency and good energy resolution for capture gamma-rays yields a further reduction of this background by using only the relevant energy channels for data evaluation. In the first measurements with the new detector, the neutron capture cross sections of {sup 93}Nb, {sup 103}Rh, and {sup 181}Ta were determined in the energy range from 3 to 200 keV relative to gold as a standard. The cross-section ratios could be determined with overall systematic uncertainties of 0.7 to 0.8%; statistical uncertainties were less than 1% in the energy range from 20 to 100 keV, if the data are combined in 20-keV wide bins. This represents an improvement of factors 5--10 compared to existing experimental methods. The necessary sample masses were of the order of one gram.

Wisshak, K.; Voss, F.; Kaeppeler, F. (Kernforschungszentrum Karlsruhe, Institut fuer Kernphysik, D-7500 Karlsruhe (Federal Republic of Germany)); Reffo, G. (Comitato Nazionale dell'Energia Nucleare e dell'Energie Alternative, I-40138 Bologna (Italy))

1990-10-01

479

Positron Mean Free Paths Between 50eV and 40KeV  

SciTech Connect

We have developed a formalism for calculating the inelastic mean free paths (IMFP's) of positrons by extending an existing semiempirical method developed by Tanuma, Powell, and Penn that is currently used for electrons. As examples, we have calculated the positron IMFP's in the 50 eV to 40 keV energy range for four different elements. In the intermediate-energy region, roughly 200 eV to 2 keV, the inelastic mean free paths for both positrons and electrons are similar. However, at lower energies, differences in correlation and exchange between the leptons during inelastic scattering events result in the inelastic mean free path being smaller for the positrons than for the electrons. At the highest energies, above about 2 keV, the relativistic correction suggested by Inokuti to the scattering cross section has been made. The resulting relativistic inelastic mean free paths are reasonable upper limits for both leptons below the bremsstrahlung regime.

Farrell, Helen Honora; Denison, A. B.

2004-03-01

480

Collaborative Writing with Web 2.0 Technologies: Education Students' Perceptions  

ERIC Educational Resources Information Center

|Web 2.0 technologies are becoming popular in teaching and learning environments. Among them several online collaborative writing tools, like wikis and blogs, have been integrated into educational settings. Research has been carried out on a wide range of subjects related to wikis, while other, comparable tools like Google Docs and EtherPad remain

Brodahl, Cornelia; Hadjerrouit, Said; Hansen, Nils Kristian

2011-01-01

481

Collaborative Writing with Web 2.0 Technologies: Education Students' Perceptions  

ERIC Educational Resources Information Center

Web 2.0 technologies are becoming popular in teaching and learning environments. Among them several online collaborative writing tools, like wikis and blogs, have been integrated into educational settings. Research has been carried out on a wide range of subjects related to wikis, while other, comparable tools like Google Docs and EtherPad remain

Brodahl, Cornelia; Hadjerrouit, Said; Hansen, Nils Kristian

2011-01-01

482

Learning with Web 2.0: Social Technology and Discursive Psychology  

ERIC Educational Resources Information Center

|Recent years have seen the rise of Internet technologies which facilitate activities that are, above all, social and participatory, allowing children and adults to create and share their own content, and to communicate in a wide range of forums. Correspondingly, there has been great popular and expert interest in the potential of Web 2.0

Friesen, Norm; Lowe, Shannon

2012-01-01

483

Cross Sections and Swarm Coefficients for Nitrogen Ions and Neutrals in N2 and Argon Ions and Neutrals in Ar for Energies from 0.1 eV to 10 keV  

Microsoft Academic Search

Graphical and tabulated data and the associated bibliography are presented for cross sections for elastic, excitation, and ionization collisions of N+, N+2, N, and N2 with N2 and for Ar+ and Ar with Ar for laboratory energies from 0.1 eV to 10 keV. Where appropriate, drift velocities and reaction or excitation coefficients are calculated from the cross sections and recommended

A. V. Phelps

1991-01-01

484

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

National Technical Information Service (NTIS)

A PC package is documented for calculating stopping powers and ranges of electrons, protons and helium ions in matter for energies from 1 keV up to 10 GeV. Stopping powers and ranges for electrons can be calculated for any element, compound or mixture. St...

M. J. Berger

1993-01-01

485

Nonmetal-metal transition in Znn (n=2 20) clusters  

NASA Astrophysics Data System (ADS)

By using density functional calculation with generalized gradient approximation, we have studied the structural and electronic properties of the zinc clusters. The lowest-energy structures of Znn (n=2 20) clusters are determined. Three kinds of growth pathways are obtained in the small zinc clusters from Zn4 to Zn8 and tetrahedron-based structures have favorable energy. The zinc clusters with 7 16 atoms are semiconductorlike. A structural transition from low coordination cagelike to high coordination compact structures is obtained around Zn17. The Znn clusters with n=4, 7, 9, 10, 14, 18, 20 show relatively high stability, consistent with the electron shell model and mass spectra. The ionization potentials of the Znn clusters are calculated and compared with conducting sphere droplet model. The size evolution of zinc clusters from van der Waals to covalent and bulk metallic behavior is discussed. The Zn clusters show stronger metallicity than the Cd and Hg clusters with same size.

Wang, Jinlan; Wang, Guanghou; Zhao, Jijun

2003-07-01

486

LANL* V2.0: global modeling and validation  

NASA Astrophysics Data System (ADS)

We describe in this paper the new version of LANL*. Just like the previous version, this new version V2.0 of LANL* is an artificial neural network (ANN) for calculating the magnetic drift invariant, L*, that is used for modeling radiation belt dynamics and for other space weather applications. We have implemented the following enhancements in the new version: (1) we have removed the limitation to geosynchronous orbit and the model can now be used for any type of orbit. (2) The new version is based on the improved magnetic field model by Tsyganenko and Sitnov (2005) (TS05) instead of the older model by Tsyganenko et al. (2003). We have validated the model and compared our results to L* calculations with the TS05 model based on ephemerides for CRRES, Polar, GPS, a LANL geosynchronous satellite, and a virtual RBSP type orbit. We find that the neural network performs very well for all these orbits with an error typically ? L* < 0.2 which corresponds to an error of 3% at geosynchronous orbit. This new LANL-V2.0 artificial neural network is orders of magnitudes faster than traditional numerical field line integration techniques with the TS05 model. It has applications to real-time radiation belt forecasting, analysis of data sets involving decades of satellite of observations, and other problems in space weather.

Koller, J.; Zaharia, S.

2011-03-01

487

SCOR: Structural classification of RNA, Version 2.0  

SciTech Connect

SCOR (http://scor.lbl.gov), the Structural Classification of RNA, is a database designed to provide a comprehensive perspective and understanding of RNA motif three-dimensional structure, function, tertiary interactions, and their relationships. SCOR 2.0 represents a major expansion and introduces a wholly new classification system. The new version represents the classification as a Directed Acyclic Graph (DAG), which allows a classification node to have multiple parents, in contrast to the strictly hierarchical classification used in SCOR 1.2. SCOR 2.0 supports three types of query terms in the updated search engine: PDB or NDB identifier, nucleotide sequence, and keyword. We also provide parseable XML files for all information. This new release contains 511RNA entries from the PDB as of 15 May 2003. A total of 5,880 secondary structural elements are classified; 2,104 hairpin loops and 3,776 internal loops. RNA motifs reported in the literature, such as ''Kinkturn'' and ''GNRA loops,'' are now incorporated into the structural classification along with definitions and descriptions.

Tamura, Makio; Hendrix, Donna K.; Klosterman, Peter

2003-10-03

488

Study of medicine 2.0 due to Web 2.0?! -- risks and opportunities for the curriculum in Leipzig.  

PubMed

Web 2.0 is changing the study of medicine by opening up totally new ways of learning and teaching in an ongoing process. Global social networking services like Facebook, YouTube, Flickr, Google Drive and Xing already play an important part in communication both among students and between students and teaching staff. Moreover, local portals (such as the platform [http://www.leipzig-medizin.de] established in 2003) have also caught on and in