Energy Technology Data Exchange (ETDEWEB)

We present the results of a comprehensive study of the temperature dependences of the quantum efficiency for ultraviolet detectors based on GaAs, GaP and 4H--SiC Schottky structures, and on Si, GaAs p-n structures. For ultraviolet detectors based on Schottky structures, the quantum efficiency increases with increasing temperature for all photon energies, even including the semiconductor intrinsic absorption region. On the other hand, for ultraviolet detectors based on p-n structures, the quantum efficiency is practically temperature independent in the semiconductor intrinsic absorption region. The change in the quantum efficiency for the GaAs and Si detectors is less than 0.01% per degree. To explain the measurements, a variable trap occupancy model is presented. Subsurface imperfections of the semiconductor cause fluctuations in the profile of the conduction ...

UK PubMed Central (United Kingdom)

Objective. For the multislice CT (MSCT) systems with a larger number of detector rows, it is essential to employ dose-reduction techniques. As...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

A comparative study by Eu-L/sub III/ X-ray absorption and /sup 151/Eu-Moessbauer spectroscopy is presented for the EuPd/sub 2-x/Au/sub x/ Si/sub 2/ series. Possible ways to distinguish between mixed-valent behaviour and final-state effects in the L/sub II /I-edge spectra are discussed.

Science.gov (United States)

Optical measurement of the Doppler shift of laser backscatter, using a near-IR, visible, or ultraviolet laser, is potentially more robust and field reliable than coherent, heterodyne measurement with an IR laser. The direct measurement of the displacement of Fabry-Perot interference fringes is possible, but entails expensive, technically challenging, imaging detectors. The 'edge technique' permits Doppler shift measurements with relatively simple detectors and detector electronics, and has been implemented with Fabry-Perot etalons and with atomic line filters. Simple analytical models of the fringe imaging and edge detection techniques are presented, permitting ready calculation of the potential performance of either, for various atmospheric conditions and for various lidar hardware configurations. The predictions of the analytical models are confirmed by computer models, which in ...

International Nuclear Information System (INIS)

We have measured K-edge X-ray absorption spectra of argon in sputtered aluminum films at a synchrotron radiation facility (the Photon Factory). We found that the energy and shape of white line change when the film is annealed at 500 C and the spectrum becomes resembling that of argon implanted in silicon. From the analyses of the X-ray absorption spectra and TEM observation we concluded that argon exists as very small atom clusters with a diameter less than 1 nm or exist as isolated atoms in the as-sputtered aluminum film, and that the size of the clusters become as big as 10 nm diameter when the film is heated. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

International Nuclear Information System (INIS)

The local environment of Ca dopants in barium titanate, BaTiO_3, is investigated by Ca K-edge X-ray absorption near-edge structure (XANES) spectroscopy. In conjunction with experiments, first-principles calculations by two methods are systematically made. The projector-augmented wave (PAW) method is used to optimize the local structure and obtain the formation energy. The augmented plane wave plus local orbitals method is adopted to obtain theoretical XANES spectra. A comparison between experimental and theoretical XANES spectra shows that Ca dopants are located at the Ba"2"+ sites forming Ca"2"+. Formation energy calculations of Ca doped BaTiO_3 by the PAW method also give the same results. The Ca atom in BaTiO_3 is off-centering in comparison with the Ba site in BaTiO_3. The off-centering of Ca atom is newly revealed by the combination of XANES spectroscopy and first-principles DFT calculations.

International Nuclear Information System (INIS)

Total photon attenuation coefficients near absorption edges are determined in certain suitable elements and compounds. Photoelectric cross sections for elements are deduced from these by subtracting the coherent and incoherent scattering cross sections as well as other elemental cross sections in the cases of compounds. Certain deviations are observed on comparison with the available theoretical and experimental compilations. The I/sub L//sub #alpha#//Il x-ray intensity ratio measured by photon excitation near threshold is found to agree better with the theory than the other available experimental data.

Energy Technology Data Exchange (ETDEWEB)

The experiments at the incinerator for low-level wastes processing, (containing transuranium radionuclides) are described. Air decontamination factors and detector readings correction factors for efficiency and absorption are indicated.

Energy Technology Data Exchange (ETDEWEB)

Measurements on laser shock compressed aluminium using the EXAFS (Extended X-ray Absorption Fine Structure) technique on the Al K-edge are described. Two methods of analysis of this data were used for the determination of density: the standard EXAFS technique using Fourier transforms and curve fitting, and a method based on a bandstructure calculation of the absorption spectra as a function of compression. These two techniques give results which are in fairly good agreement with each other and also with a hydrodynamic simulation of the experiment. The ion correlation parameter is estimated and shows that two-sided laser irradiation of aluminium foils produces a dense plasma which is strongly coupled. (author).

International Nuclear Information System (INIS)

Layer-by-layer formation for #pi#-conjugated azomethine multilayers bonded on substrates was investigated. The multilayers were synthesized using ethanol (EtOH) and dichloromethane (DCM) as reaction solvents. The multilayer characteristics were analyzed using UV-vis absorption spectroscopy, ellipsometric thickness, and atomic force microscopy. The absorption spectra and ellipsometric thicknesses of multilayers formed using EtOH and DCM were compared. The results indicate that EtOH is more suitable than DCM for such layer-by-layer formation. In addition, bandgaps estimated from the absorption edge of multilayers were investigated. The results indicate that the bandgap decreases as the number of benzene rings contained in the molecular chain of the multilayer increases. Also, a multilayer with four benzene rings bonded on a substrate had a bandgap close to that of a polymer with a similar chemical ...

Energy Technology Data Exchange (ETDEWEB)

A method has been developed to optimize the energy resolution of a horizontally focusing monochromator. The method consists of determining the optimum radius of curvature of the cylindrically bent monochromator crystal by minimizing the total diffracted X-ray flux measured through an X-ray absorption foil. When measured at an absorption edge a global minimum can be identified, which corresponds to the minimum energy band accepted along the entire length of the crystal. Experimental verification of this method has been validated by comparing X-ray fluorescent scans taken for a series of crystal curvatures and by directly measuring the X-ray beam profiles at the corresponding points. The actual optical configuration and asymmetric-cut parameter of the focusing monochromator on beamline X4C at the National Synchrotron Light Source are modeled and ray tracing simulations of the optical system are compared with direct beam ...

Energy Technology Data Exchange (ETDEWEB)

A new generation of quasimonochromatic high-flux X-ray sources, based on the X-ray radiation produced through Compton scattering between an electron beam and a laser beam, is under development. One of the possible applications of this source is inline phase contrast mammography, based on the observation of the edge-enhancement effect that can be observed at the border of structures inside the breast in images produced using a partially or totally coherent X-ray beam. In this work we present the results of a set of simulations of inline phase contrast mammography using typical inverse Compton scattering sources parameters. The simulated sample was a tumour-like mass having spherical shape, diameter between 200 {mu}m and 5 mm, placed inside a breast-like matrix, 4 cm thick, and a standard composition of 50% glandular tissue and 50% adipose tissue. We discuss the minimum requirements for mammography using inverse Compton scattering sources and we discuss how the ...

International Nuclear Information System (INIS)

Purpose/Objective: At present, treatment verification between portal and reference images is performed based on manually-identified features by radiation oncologist, which is both time-consuming and potentially error-prone. There is a demand for the computerized verification procedure in clinical application. The purpose of this study is to develop a computerized portal verification scheme for pelvic treatment fields. Materials/Methods: The automated verification system involves image acquisition, image feature extraction, feature matching between reference and portal images and quantitative evaluation of patient setup. Electronic portal images with a matrix size of 256 x 256 and 12 bit gray levels were acquired using a liquid matrix electronic portal imaging device. Simulation images were acquired by digitizing simulation films using a TV camera into images with 256 x 256 matrix and 8 bit gray levels. Initially a Canny edge detector is applied ...

Energy Technology Data Exchange (ETDEWEB)

The development and evaluation of a post-column reaction detector sensitive to platinum(II) complexes is presented in which sodium bisulfite is used as the derivatizing agent with potassium dichromate as an activating agent. The influences of mobile phase changes (i.e., pH, organic modifiers, electrolytes), oxygen, metal ions, and order of reagent addition on reaction kinetics and product yield are defined and used in optimization of detector response. Detection at lambda/sub max/ 290 nm results in an on-line post-column sensitivity of 40-60 ng/mL for selected cis-dichloroplatinum complexes and a sensitivity of 300-1200 ng/mL for four (substituted)-malonato-platinum complexes. The reaction detector is used to monitor the kinetics of aquation of cisplatin (CDDP) and to quantitate CDDP degradation in plasma. As the sensitivity for CDDP in plasma is comparable to that achieved from high pressure liquid chromatography (HPLC) ...

International Nuclear Information System (INIS)

GaN and Al_1_-_xGa_xN films were grown by the method of ECR-MBE. Absorption constants as a function of wavelength were determined from transmission measurements. Photoconducting detectors were fabricated from these films and characterized in terms of their spectral response and photoconductive gain. Mobility-lifetime products were determined from the measurement of photoconductive gain. The resistivity and mobility-lifetime products of the films were varied from 10--10"9 ohm-cm and 10"-"3--10"-"8 cm"2/V respectively by changing the microwave power in the ECR discharge from 20--60 watts. The change in the mobility-lifetime product is attributed to change in the lifetimes of the photogenerated carriers. This assumption is supported by direct measurement of detector response times. Finally, the authors report for the first time, the detection of alpha particles using GaN detectors.

CERN Document Server

The stellar disc kinematics in a sample of fifteen intermediate- to late-type edge-on spiral galaxies are studied using a dynamical modeling technique. The sample covers a substantial range in maximum rotation velocity and deprojected face-on surface brightness and contains seven spirals with either a boxy- or peanut-shaped bulge. Dynamical models of the stellar discs are constructed using the disc structure from $I$-band surface photometry and rotation curves observed in the gas. The differences in the line-of-sight stellar kinematics between the models and absorption line spectroscopy are minimized using a least-squares approach. The modeling constrains the disc surface density and stellar radial velocity dispersion at a fiducial radius through the free parameter $\\sqrt{M/L}$ $(\\sigma_{\\rm z}/\\sigma_{\\rm R})^{-1}$, where $\\sigma_{\\rm z}/\\sigma_{\\rm R}$ is the ratio of vertical and radial velocity dispersion and $M/L$ the disc ...

Science.gov (United States)

Charge flow and valence/d-band behavior in ion-beam-mixed (IBM) Pd1-xAgx (x = 0.5-0.9) alloys have been studied by X-ray photoemission measurement of the valence bands and of core-level binding energy shifts and X-ray absorption near-edge structure. We correlated the observed Ag 3d5/2 core-level shifts in these IBM alloys, relative to the elemental Ag, with the White Line area changes at the Pd and Ag L3-edge to investigate the charge redistribution at the Ag site. The results indicate that there is a decrease in sp-like conduction electron and a negligible change in the number of d-electrons at the Ag site upon alloying. These results are in line with our previous results in which Pd gains d-charges and loses sp-type charges. This electron redistribution due to hybridization in the alloy leads small net charge transfer from the Ag site to the Pd site in accordance with electronegativity predictions. This result is ...

Energy Technology Data Exchange (ETDEWEB)

Elemental analysis of some medicinal plants used in the Indian Ayurvedic system was performed by employing instrumental neutron activation analysis (INAA) and atomic absorption spectroscopy (AAS) techniques. The samples were irradiated with thermal neutrons in a nuclear reactor and the induced activity was counted by gamma ray spectrometry using an efficiency calibrated high resolution high purity germanium (HPGe) detector. Most of the medicinal plants were found to be rich in one or more of the elements under study. The variation in elemental concentration in same medicinal plants samples collected in summer, winter and rainy seasons was studied and the biological effects of these elements on human beings are discussed. (orig.)

International Nuclear Information System (INIS)

The invention refers a procedure of radiation dose control in irradiated tissues during electron-beam therapy. It aims at meeting the planned radiation dose for diseased tissues and taking care of the healthy ones. Therefore, the dose distribution required is determined before irradiation in consideration of such factors as energy-dependence of detector sensitivity, self-absorption within the tissue, and relative biological effectiveness. Furthermore, the expected intensity distribution of secondary quantum radiation excited in the irradiated tissue is calculated. A radiation detector for local resolution is used for registration. During irradiation the calculated intensity distribution is compared with the measured one. The invention is applicable in radiation therapy with monoenergetic electron beams.

British Library Electronic Table of Contents (United Kingdom)

Fe-doped TiO2 hollow spheres (Fe-THs) were synthesized by sol?gel process using carbon spheres as templates. The prepared samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), UV?vis diffuse reflectance spectrum (DRS), N2 adsorption?desorption isotherms, Electron paramagnetic resonance (EPR) spectroscopy and Photoluminescence emission spectroscopy (PL). UV?vis spectra showed that Fe3+ doping could extend the absorption edge to the visible region. EPR spectra showed that Fe3+ was incorporated into the crystal lattice of TiO2, which could inhibit the recombination of photo-induced electron?hole pairs and improve the photocatalytic activity. The photocatalytic activities of the prepared samples were evaluated for the degradation of dye Reactive Brillia...

International Nuclear Information System (INIS)

Experimentally, a feasibility study for adsorption and catalytic pyrolysis of spill oils on Cu/ZSM-5 for recycling of light oils has been conducted in the present work. The adsorption and pyrolysis of model compounds such as heptane, toluene, and diesel (to stimulate the spill oils) on Cu/ZSM-5 have been investigated on a continuous fixed-bed reactor. By component fitted X-ray absorption near edge structural (XANES) spectroscopy, catalytic active species such as metallic copper (Cu) (77-84%) and Cu2O (6-7%) are found in the channels of ZSM-5 during pyrolysis of heptane or toluene. Pyrolysis of diesel effected by Cu/ZSM-5 yields gas (C1-C5) (32%) and light oil (68%) that can be used as auxiliary fuels.

International Nuclear Information System (INIS)

Cerium L_3 XANES (x-ray-absorption near-edge-structure) spectra were analyzed to separate Ce moment contributions and mixed valence (MV) in complex magnetic silicides CePd_2_-_xMn_xSi_2 (0#<=#x#<=#2). The Ce valence mixing does not vary linearly with x, but increases rapidly for x#>=#1.5. The associated moment collapse correlates with pronounced deviations of the unit-cell volume from Vegard law and the onset of structural instability. Reorientation of [001] Mn 3d antiferromagnetic order for x<2 appears to rapidly suppress the weak Ce valence mixing coexisting with antiferromagnetic order in CeMn_2Si_2.

Science.gov (United States)

The Micro-X instrument is a NASA funded, rocket borne X-ray imaging spectrometer planned for launch in January 2011. An array of Transition Edge Sensors (TESs) will observe incoming photons in the 0.2-3 keV energy band with an energy resolution of 2-4 eV at 1 keV. This will be a substantial improvement over current non-dispersive detectors for X-ray spectroscopy of extended sources and will be the first demonstration of a TES-based microcalorimeter in space. The TESs will utilize the 50 mK stage of an Adiabatic Demagnetization Refrigerator (ADR) as a heat sink, and will be read out by a SQUID time division multiplexer. X-rays will be focused onto the TES array of 128 pixels on a 600 micron pitch by a conically approximated Wolter optic with an effective area of 200 cm2. The spectrometer will have a field of view of 11.8 arcmin. We describe the design and development progress of the instrument.

International Nuclear Information System (INIS)

Radionuclide X-ray fluorescence analysis for nondestructive determination of Fe, Zn, Pb, and Br in air samples collected on nitrocellulose membrane filter Synpor 4 is described. A "2"3"8Pu source for the excitation and a semiconductor Si/Li detector for the detection of characteristic and L-fluorescent radiation of the above elements were used. A correction method based upon the measurements of simple or multiple Compton scattering for compensation of varying mass per unit area values in sample deposits was theoretically proposed and experimentally tested. The results obtained both with and without the correction were compared and good agreement with those given by atomic absorption spectrometry was observed. (author).

British Library Electronic Table of Contents (United Kingdom)

A WO3/TiO2 composite, hollow-sphere photocatalyst with average diameter of 320nm and shell thickness of 50nm was successfully prepared using a template method. UV-vis diffuse reflectance spectra illustrated that the main absorption edges of the WO3/TiO2 hollow spheres were red-shifted compared to the TiO2 hollow spheres, indicating an extension of light absorption into the visible region of the composite photocatalyst. The WO3 and TiO2 phases were confirmed by X-ray diffraction analysis. BET isotherms revealed that the specific surface area and average pore diameter of the hollow spheres were 40.95m^2/g and 19nm, respectively. Photocatalytic experiments indicate that 78% MB was degraded by WO3/TiO2 hollow spheres under visible light within 80min. Under the same conditions, only 24% MB can ...

Energy Technology Data Exchange (ETDEWEB)

The Helium and Lead Observatory (HALO) is a supernova neutrino detector under development for construction at SNOLAB. It is intended to fulfill a niche as a long term, low cost, high livetime, and low maintenance, dedicated supernova detector. It will be constructed from 80 tonnes of lead, from the decommissioning of the Deep River Cosmic Ray Station, and instrumented with approximately 384 meters of {sup 3}He neutron detectors from the final phase of the SNO experiment. Charged- and Neutral-Current neutrino interactions in lead expel neutrons from the lead nuclei making a burst of detected neutrons the signature for the detection of a supernova. Existing neutrino detectors are mostly of the water Cerenkov and liquid scintillator types, which are primarily sensitive to electron anti-neutrinos via charged-current interactions on the hydrogen nuclei in these materials. By contrast, the large neutron ...

International Nuclear Information System (INIS)

In the microwave tokamak experiment (MTX) program, we are concentrating on experiments using intense, free-electron laser (FEL) generated microwave pulses. In initial FEL experiments, several diagnostic instruments were operated during injection of microwave pulses with peak powers to 0.2 GW at durations of 10 ns. Fixed and spatially scanning microwave detectors and receivers and a 48-element calorimeter on the inside wall of MTX diagnosed the GW-level FEL microwave pulses. With these diagnostics, linear-wave absorption and efficiencies of transmission through the quasi-optical transport system were studied. In addition, several radially resolved measurements of plasma density, temperature, and emission were made during FEL injection and were used in the analysis of microwave absorption data. A timing system, slaved to the FEL pulse arrival time, is capable of accuracy to a few nanoseconds in order to allow measurement of ...

International Nuclear Information System (INIS)

The Polarized Gamma-ray Observer (PoGOLite) is a balloon-borne instrument that will measure gamma-ray polarization in the energy range 25-80 keV from astronomical sources such as pulsars, accretion discs and jets from active galactic nuclei. The two additional parameters provided by such observations, polarization angle and degree, will allow these objects to be studied in a new way, providing information about their emission mechanisms and geometries. The instrument measures azimuthal scattering angles of photons within a close packed array of phoswich detector cells (PDCs) based on coincident detection of Compton scattering and photoelectric absorption. Each PDC comprises three different scintillating components and combines photon detection, active collimation and bottom anticoincidence into one single unit. The three parts are viewed by a photomultiplier tube (PMT) and pulse shape discrimination is used to identify signals from dierent ...

Energy Technology Data Exchange (ETDEWEB)

Radionuclide X-ray fluorescence analysis for nondestructive determination of Fe, Zn, Pb, and Br in air samples collected on nitrocellulose membrane filter Synpor 4 is described. A /sup 238/Pu source for the excitation and a semiconductor Si/Li detector for the detection of characteristic and L-fluorescent radiation of the above elements were used. A correction method based upon the measurements of simple or multiple Compton scattering for compensation of varying mass per unit area values in sample deposits was theoretically proposed and experimentally tested. The results obtained both with and without the correction were compared and good agreement with those given by atomic absorption spectrometry was observed.

Energy Technology Data Exchange (ETDEWEB)

Mass and charge distributions of products from fission of sup(242m)Am induced by thermal neutrons have been investigated by means of the semiconductor spectrometry of ..gamma.. radiation from a mixture of non-separated fragment nuclei. Specimens of the fissible material have been irradiated in the vertical experimental channel of the research reactor then the measurements have been performed with calibrated semiconductor detectors. Three experiments with substantially different irradiation times have been performed to expand the nomenclature of the investigated fission products. The spectra of ..gamma.. radiation from the mixture of fission products, and time dependences of the counting rates at the total absorption peaks have been handled with computers. The obtained yields are compared with data of previous investigations performed with different experimental methods, as well as with the calculated one.

Science.gov (United States)

Language: English ...

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

Energy Technology Data Exchange (ETDEWEB)

Crystalline MnMoO{sub 4} was synthesized using a conventional solid reaction method and investigated for its physical and electrochemical properties as an anode material for Li secondary battery. The reversible amount of Li insertion/removal of MnMoO{sub 4} anode during the first cycle was about 800 mA h/g, accompanied by irreversible structural transformation into amorphous material. The amorphization during the first Li insertion was investigated by structural analysis using XRD of electrode. The charge compensation during Li insertion/removal was examined by measurement of X-ray Absorption Near Edge Structure (XANES) spectroscopy. Despite its irreversible structural transformation to amorphous during the first lithiation, subsequent cycles showed a reasonable cyclability. This paper presents the electrochemical properties of MnMoO{sub 4} and discusses the mechanism underlying the Li insertion/removal process.

International Nuclear Information System (INIS)

Buried silicon carbide (SiC) microstructures with lateral dimensions in the #mu#m range were formed by high-dose projection of 1.5 MeV C"2"+ ions in Si(100) at different doses and temperatures and subsequent annealing for 10 h at 1250 deg. C. Sections of individual SiC microstructures were prepared for cross-sectional transmission electron microscopy (TEM) analysis using a focused ion beam (FIB). Besides the possibility to select an individual microstructure, the FIB technique has the advantage of producing specimen foils of uniform thickness. Therefore, it was possible to map the carbon concentration of microstructures by energy filtered TEM (EFTEM) using the C_K absorption edge without the need of any sample thickness correction. Local overstoichiometric (>50%) carbon concentrations are shown to be correlated to the formation of an amorphous phase in the SiC and to significant swelling visible at the Si wafer surface 2 #mu#m above.

International Nuclear Information System (INIS)

The structural, morphological and optical properties of vacuum-evaporated CdTe thin films were investigated as a function of substrate temperature and post-deposition annealing without and with CdCl2/treatment at 400 C for 30 min. Diffraction patterns are almost the same exhibiting higher preferential orientation corresponding to (111) plane of the cubic phase. The intensity of the (111) peak increased with the CdCl2/annealing treatment. The microstructure observed for all films following the CdCl2/annealing treatment are granular, regardless of the as-deposited microstructure. The grain sizes are increased after the CdCl2/annealing treatment but now contain voids around the grain boundaries. The optical band gaps, Eg, were found to be 1.50, 1.50 and 1.48 eV for films deposited at 200 K and annealed without and with CdCl2/treatment at 400 C for 30 min respectively. A progressive sharpening of the absorption edge upon heat treatment particularly ...

Energy Technology Data Exchange (ETDEWEB)

In portal images with high energy X-ray (10 MV), it is sometimes difficult to verify the irradiation field because of the low contrast. Especially, in the abdominal and pelvic region, the deterioration of portal image quality is remarkable. To solve this problem, we took portal images using computed radiography (FCR). Also, we develop a technique in which a copper plate (3 mm) and lead foil (0.3 mm) are closely set in the front and rear of the photostimulable phosphor plate (imaging plate), for increased energy absorption. As a result, image quality was very high and we confirmed image improvement using observer performance experiments. We made a special cassette which can closely set metallic plates to imaging plate and load FCR-7000 directly. Therefore, image process becomes simple, and suitable for routine work. In computed radiography, image processing (tone scale modification and edge enhancement) is possible, and is advantageous portal ...

Energy Technology Data Exchange (ETDEWEB)

Eu 4f electronic structures of a temperature-induced valence transition system EuPd{sub 2}Si{sub 2} have been investigated by bulk-sensitive high-resolution photoemission spectroscopy at temperatures from 20 to 300 K. The bulk Eu{sup 2+} 4f component is definitely distinguished from two surface Eu{sup 2+} 4f components. The changes in the spectral intensity of the bulk Eu{sup 2+} and Eu{sup 3+} 4f configurations and in the energy separation between these states are observed in the temperature dependent photoemission spectra. These temperature dependences are related to the valence transition of EuPd{sub 2}Si{sub 2}. The Eu mean valence is evaluated to be 2.75{+-}0.03 at 20 K and 2.30{+-}0.05 at 300 K. These values are in good agreement with those evaluated from Moessbauer and Eu L{sub III}-edge X-ray absorption measurements.

Science.gov (United States)

The Micro-X instrument is a rocket borne, X-ray imaging spectrometer planned for launch in October 2011. An array of 128 Transition Edge Sensors (TESs) on a 600 micron pitch will observe incoming photons in the 0.2-3 keV energy band with an energy resolution of 2-4 eV at 1 keV. X-rays will be focused onto the TES array by a conically approximated Wolter optic with an effective area of 300 cm^2 giving the instrument a field of view of 11.8 arcmin. This performance will constitute a substantial improvement over current non-dispersive detectors for X-ray spectroscopy of extended sources and will be the first demonstration of a TES-based microcalorimeter in space. The TESs will utilize the 50 mK stage of an Adiabatic Demagnetization Refrigerator (ADR) as a heat bath, and will be read out by a SQUID time division multiplexer. The first flight of the Micro-X instrument will observe the Puppis A supernova remnant. Future targets include the core of ...

Energy Technology Data Exchange (ETDEWEB)

Manganese model complexes, relevant to the oxygen-evolving complex (OEC) in photosynthesis, were studied with Mn K-edge X-ray absorption near-edge spectroscopy (XANES), Mn Kb X-ray emission spectroscopy (XES), and vibrational spectroscopy. A more detailed understanding was obtained of the influence of nuclearity, overall structure, oxidation state, and ligand environment of the Mn atoms on the spectra from these methods. This refined understanding is necessary for improving the interpretation of spectra of the OEC. Mn XANES and Kb XES were used to study a di-(mu)-oxo and a mono-(mu)-oxo di-nuclear Mn compound in the (III,III), (III,IV), and (IV,IV) oxidation states. XANES spectra show energy shifts of 0.8 - 2.2 eV for 1-electron oxidation-state changes and 0.4 - 1.8 eV for ligand-environment changes. The shifts observed for Mn XES spectra were approximately 0.21 eV for oxidation state-changes and only approximately 0.04 eV ...

Science.gov (United States)

The traditional wing control surfacestrailing edge ailerons and the outboard leading edge flapsare used to provide the aerodynamic force needed to twist ...

CERN Document Server

CZT Detector and HXI Development at CASS/UCSD

Energy Technology Data Exchange (ETDEWEB)

Metal nanoparticles have many potential technological applications. Biological routes to the synthesis of these particles have been proposed including production by vascular plants, known as phytoextraction. While many studies have looked at metal uptake by plants, particularly with regard to phytoremediation and hyperaccumulation, few have distinguished between metal deposition and metal salt accumulation. This work describes the uptake of AgNO{sub 3}, Na{sub 3}Ag(S{sub 2}O{sub 3}){sub 2}, and Ag(NH{sub 3}){sub 2}NO{sub 3} solutions by hydroponically grown Brassica juncea and the quantitative measurement of the conversion of these salts to silver metal nanoparticles. Using X-ray absorption near edge spectroscopy (XANES) to determine the metal speciation within the plants, combined with atomic absorption spectroscopy (AAS) for total Ag, the quantity of reduction of Ag{sup I} to Ag{sup 0} is reported. Transmission electron ...

Science.gov (United States)

A WO(3)/TiO(2) composite, hollow-sphere photocatalyst with average diameter of 320 nm and shell thickness of 50 nm was successfully prepared using a template method. UV-vis diffuse reflectance spectra illustrated that the main absorption edges of the WO(3)/TiO(2) hollow spheres were red-shifted compared to the TiO(2) hollow spheres, indicating an extension of light absorption into the visible region of the composite photocatalyst. The WO(3) and TiO(2) phases were confirmed by X-ray diffraction analysis. BET isotherms revealed that the specific surface area and average pore diameter of the hollow spheres were 40.95 m(2)/g and 19 nm, respectively. Photocatalytic experiments indicate that 78% MB was degraded by WO(3)/TiO(2) hollow spheres under visible light within 80 min. Under the same conditions, only 24% MB can be photodegraded by TiO(2). The photocatalytic mineralization of MB, catalyzed by TiO(2) and WO(3)/TiO(2), ...

Energy Technology Data Exchange (ETDEWEB)

Phase-contrast imaging with a practical cone-beam X-ray tube has been realized for clinical use in digital mammography using computed radiography (CR). To perform phase-contrast imaging, the X-ray detector must be distanced from an object so that the phase-contrast image achieves magnification; in a mammography unit dedicated to phase-contrast imaging, the magnification ratio is 1.75. When using an X-ray tube with a 0.1-mm focal spot, it appears that the penumbra in magnification blurs both projected images and the phase contrast, which generates an edge effect. However, where the sampling pitch of the CR plate is 43.75 {mu}m, the blur stretches the width of the phase contrast so that unit pixels in the detector can capture it. Note that the width of an ideal phase contrast using an X-ray point source results in a phase contrast too narrow for detection with CR. In addition to phase contrast improving image quality, a ...

Energy Technology Data Exchange (ETDEWEB)

The WAND (Waste Assay for Nonradioactive Disposal) system can scan thought-to-be-clean, low-density waste (mostly paper and plastics) to determine whether the levels of any contaminant radioactivity are low enough to justify their disposal in normal public landfills or similar facilities. Such a screening would allow probably at least half of the large volume of low-density waste now buried at high cost in LANL`s Rad Waste Landfill (Area G at Technical Area 54) to be disposed of elsewhere at a much lower cost. The WAND System consists of a well-shielded bank of six 5-in.-diam. phoswich scintillation detectors; a mechanical conveyor system that carries a 12-in.-wide layer of either shredded material or packets of paper sheets beneath the bank of detectors; the electronics needed to process the outputs of the detectors; and a small computer to control the whole system and to perform the data analysis. WAND system minimum ...

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

KoreaScience (Korea)

Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Bremstrahlung Isochromat Spectroscopy (BIS). The XES spectra were collected using a Specs electron gun for the excitation and the XES 350 grating monochromator and channel plate system from Scienta as the photon detection. Spectra were collected in 'normal mode,' where the electron gun kinetic energy (KE) and the energy position of the center of the channel plate were both fixed and the energy distribution in the photon (hv) spectrum was derived from the intensities distributed across the channel plate detector in the energy dispersal direction. The polycrystalline Ce sample was oxidized by exposure to air at ambient pressures. After introduction to the ultra-high vacuum system, the oxidized sample was bombarded with Ar, to clean the topmost surface region and stabilize the surface and near surface regions. Although CeO{sub 2} would be the thermodynamically preferred composition in an oxygen rich environment, the combination of a vacuum ...

Science.gov (United States)

Using static Michelson interferometer to get the spectrum information of measurement targets for spectrum identification, under the condition that the interference length is constant, the system can be optimized by BP neural network algorithm for the mixed spectral separation process. Thereby it can realize improving the recognition probability of camouflage target. Collecting the spectrum information in field of view (FOV) by the interferometer and linear array CCD detector, composing the set of mixed spectrum data, with known absorption spectrum of the material as a hidden layer of rules, it used BP neural network to separate the mixed spectrum data. Experiment with different distances, different combinations of mixed background spectrum as the initial data, using steel target (size: 1.5 m x 1.5 m) made of four kinds, the recognition probability of non-camouflage target is about 90% by BP neural network algorithm or the traditional algorithm, ...

Energy Technology Data Exchange (ETDEWEB)

This human investigation of lead absorption from the lungs utilized two forms of lead, lead chloride and lead hydroxide; the former was used in picogram amounts and the latter at microgram levels. These two species of lead were selected in an attempt to simulate the range of physicochemical properties found in atmospheric lead (urban air). Aerosols labeled with lead-203 were made of comparable aerodynamic size by using sodium chloride as the deposition-determining aerosol. After brief, mouthpiece exposures, 17 subjects were followed by serial counting with a thoracic array of scintillation detectors and two leg counters. Serial blood samples were also taken. The two exposure groups showed similar total deposition values (23 vs 26%) and the same biological retention halftimes, viz., 22.6 hr. When the retention data were corrected for blood-borne /sup 203/Pb, the biological halftimes for lung lead retention averaged 13.1 and 14.2 hr, ...

International Nuclear Information System (INIS)

A combination of measuring instruments, consisting of a Beta-Sedimeter and a radionuclide X-ray fluorescence instrument, is described. With the Beta-Sedimeter the C-14-radiation is measured. Through direct irradiation with photons of a Pu238-source in an ancillary irradiation chamber and energy dispersing measurement of the K- and L-radiation resp. of the excited heavy metals with the aid of a Si(Li)-semiconductor detector and a 4-channel analyzer the heavy metal concentrations of the heavy metals Zn, Cr, Ni and Pb are determined. For the determination of cadmium the indirect excitation with Am-241 and Dy-targets is described. The system produces records and operates fully automatically in a step-by-step mode with a testing cycle of 45 minutes. In connection with the process monitoring of the wastewater from a zinc plating plant during a period of 8 months the concentration of the solid material and of the metals Cr and Zn, which were considered to be ...

International Nuclear Information System (INIS)

Tritium, a beta emitting gas at room temperature causes a biological hazard in the locations where it is present beyond acceptable limits. The hazard can be due to inhalation, and absorption by skin. Hence is the necessity of Tritium monitoring instruments/systems for ensuring safety in the PHWRs and the nuclear research plants and laboratories. It is desirable that the instruments address satisfactorily to certain factors like the following: (i) Wide range of Tritium concentrations - 1 to 104 DAC ( Derived Air Concentration) (ii) On-line monitoring features (iii) Small response time (On-spot instantaneous measurements) (iv) Portability (v) Mitigation of memory effects. This paper presents an overview of the Online Tritium in Air Monitoring Systems manufactured by ECIL for Pressurised Heavy Water Reactors at Tarapur, Kaiga, and Rawatbhata. Significant aspects of design, function, testing, limitations of the detectors and electronics and the ...

Energy Technology Data Exchange (ETDEWEB)

To study CdZnTe as a high energy resolution gamma ray detector with a novel new design, and to build a detector array from the new detector design

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

International Nuclear Information System (INIS)

... biological effects body burden diet intestinal absorption lead lead 203 man

CERN Multimedia

Small world when building a particle detector prototype, the devil is in the tiny details

Energy Technology Data Exchange (ETDEWEB)

The gastrointestinal absorption of lead was markedly increased in human subjects who had fasted before ingesting lead. Food in the gut was found to reduce lead absorption, and the effect of dietary constituents on /sup 203/Pb absorption was investigated. The greatest reduction in absorption was caused by minerals. This dependence of lead absorption on dietary constituents complicates the establishment of safe levels of lead in food and water.

International Nuclear Information System (INIS)

Innumerable fissures were formed widely in Hanshin area in Japan by the former southern Hyogo prefectural earthquake occurred on Jan.17, 1995. In this study, as a preliminary investigation, we applied passive type radon detector Pico-Rad (U.S. Packard Instrument Co. Ltd.) with hemispheric plastic cover over them around the fissure along on the bank of two reservoirs to examine whether there is possibility to find fissures using the characteristics of "2"2"2Rn migration. One of the reservoir, Taniyamakami-ike, is located at the north of the Awaji-shima island at a distance of about 4 km from the seismic center of this earthquake. On the whole, "2"2"2Rn exhalation rates were high on a line of 2 m below the edge of the bank and got lower in proportion to the distance from this line. Those top of the bank had middle values among the lines. The mean "2"2"2Rn exhalation rate was 4.7 mBq m"-"2 s"-"1, and in these data we found some singularly high ...

KoreaScience (Korea)

Full Text Available

International Nuclear Information System (INIS)

... edge localized modes h-mode plasma confinement jet tokamak l-mode plasma

Energy Technology Data Exchange (ETDEWEB)

The crystal structure and the luminescence properties of a new carbonate, Na{sub 3}Eu(CO{sub 3}){sub 3}, are presented. Na{sub 3}Eu(CO{sub 3}){sub 3} is orthorhombic, acentric, Ama2, Z = 4; a = 9.942(2) {angstrom}, b = 11.024(3) {angstrom}, c = 7.147(2) {angstrom}; R = 0.019, R{sub w} = 0.051, 2374 unique reflections. The anionic subnetwork is built up from the stacking of {open_quotes}standing on edge{close_quotes} and {open_quotes}flat lying{close_quotes} carbonate layers into which Na{sup +} and Eu{sup 3+} ions are inserted. The symmetry of the EuO{sub 9} polyhedra is C{sub s}. The Eu{sup 3+} ions are inserted. The symmetry of the EuO{sub 9} polyhedra is C{sub s}. The Eu{sup 3+} luminescence technique confirms the presence of a unique low symmetry site for the rare earth atom. The electrostatic crystal field (cf) effects on the {sup 7}F multiplet are evaluated on the basis of the phenomenological cf theory. The simulation using C{sub 2v} symmetry for the rare ...

Energy Technology Data Exchange (ETDEWEB)

A method for using in situ X-ray absorption near edge spectroscopy to determine the composition of passive, transpassive, and nonreducible thin oxide films is described. The method is demonstrated by determining the composition of the passive films formed in pH 4.5, 0.1 M acetate buffer, on 100 {angstrom} thick Fe-yCr alloys (y = 8.5, 15, 19, 23 atom %) at potentials: (1) low in the passive region ({minus}0.3 V vs. mercurous sulfate reference electrode, MSE); (2) high in the passive region; (3) in the transpassive region; and (4) in the cathodic region where the air-formed film is not fully reduced. The nonreducible film at {minus}1.2 V is entirely a Cr{sup 3+} oxide/hydroxide. This nonreducible film persists at anodic potentials. At {minus}0.3 V, the passive film on each alloy is significantly enriched in Cr. The film at {minus}0.3 V consists primarily of the nonreducible Cr{sup 3+} oxide/hydroxide plus a very small amount of additional ...

International Nuclear Information System (INIS)

The Physikalisch-Technische Bundesanstalt (PTB), Germany's national metrology institute, developed an alignment strategy to specify elemental depth profiling in vertical sidewall layers on structured wafers. For this purpose, PTB's irradiation chamber for 200 mm and 300 mm silicon wafers was used to combine total-reflection X-ray fluorescence (TXRF) and grazing incidence XRF (GIXRF) techniques by employing monochromatized undulator radiation of the BESSY II electron storage ring. 3-D test structures were fabricated to develop an optimal alignment strategy allowing for depth profiling in such nanolayers. The test structures consisted of silicon bars with widths/spacings either in the ?m or in the nm range. In order to be able to differentiate the sidewalls more easily from the remainder of the structures, they were provided with an additional silicon nitride layer. Four structure types of different bar width and density parameters on two 200 mm silicon wafers were investigated. The ...

International Nuclear Information System (INIS)

Time resolved phase transition and strain experiments have been performed on the millisecond time scale using a Bragg-edge transmission technique that has been developed at the Los Alamos National Laboratory. The precision with which lattice parameters can be determined from edge positions is sufficient to perform high-resolution strain measurements in uniaxial stress.

International Nuclear Information System (INIS)

Personnel radiation monitoring is essential to the operation of any nuclear facility and work in this area continues to strive for an accurate determination of personnel dose. In particular recent attention has been focused upon the need to improve the accuracy of neutron dosimetry, mainly because of their high Relative Biological Effectiveness. In this work the feasibility of using the NE-213 liquid scintillation detector as an efficient neutron/#gamma# ray radiation monitor is demonstrated. Derivative method spectrum unfolding used in MATXUF for on-line analysis of fast neutron spectra has also been applied to real time #gamma# spectrum unfolding (MATXUF2), making possible simultaneous on-line monitoring of both fast neutrons and gammas. To eliminate the negative fluxes in the unfolded #gamma# spectra created by the photopeak-Compton edge combination in the plateau portion of the knee response, correcting equations using a linearized ...

Science.gov (United States)

A novel phantom has been developed to measure the modulation transfer function (MTF) in 3D for x-ray computed tomography. The phantom consists of three tungsten wires, positioned nearly orthogonal to each other. Simultaneous measurements of the MTF are taken at various locations along the three orthogonal reconstructed planes. Our computed mammotomography (CmT) system uses a Varian Paxscan 2520 digital x-ray detector which can be positioned anywhere in ~2pi steradian band and can have arbitrary trajectories. With a half-cone beam geometry and with the phantom positioned near the center of rotation, projection images are acquired over 360 degrees. Various 3D orbits are evaluated including vertical axis of rotation and saddle. Reconstructions were performed using an iterative ordered-subsets transmission algorithm on rebinned projection images, using various numbers of iterations. Rotation of reconstructed slices isolated each wire into its own plane. At various ...

CERN Document Server

We study the behavior of the Chern classes of graph hypersurfaces under the operation of deletion-contraction of an edge of the corresponding graph. We obtain an explicit formula when the edge satisfies two technical conditions, and prove that both these conditions hold when the edge is multiple in the graph. This leads to recursions for the Chern classes of graph hypersurfaces for graphs obtained by adding parallel edges to a given (regular) edge. Analogous results for the case of Grothendieck classes of graph hypersurfaces were obtained in previous work. Both Grothendieck classes and Chern classes were used to define `algebro-geometric' Feynman rules. The results in this paper provide further evidence that the polynomial Feynman rule defined in terms of the Chern-Schwartz-MacPherson class of a graph hypersurface reflects closely the combinatorics of the corresponding graph. The ...

International Nuclear Information System (INIS)

For the first time a segmented n-type HPGe detector was operated directly submerged in liquid nitrogen over a long period. As this kind of detector is envisioned to be used in GERDA phase II, it was operated with a low mass signal cable with snap-contacts and mounted in a low-mass copper holder. The detector performance was stable over 146 days, indicating that neither detector nor contacts deteriorated.

International Nuclear Information System (INIS)

The operation principle, construction and characteristics of the Bragg curve spectroscopy detector (BCS detector) are described. The electric field of the BCS detector is parallel to the particle trajectories. The detector was tested by 8.78 MeV and 6.02 MeV #alpha# particles from a ThC-ThC's source. The energy resolutions are 1.5% and 2.6% respectively for two groups of #alpha# particles, and the charge resolution is 2.7%. Further test experiments with heavy ions will be arranged.

Energy Technology Data Exchange (ETDEWEB)

A prototype detector based on the inclined absorber layer principle is introduced. For the Liquids Reflectometer at the Spallation Neutron Source, it is shown to be a significant improvement over its current detector, which imposes an instantaneous count rate limitation of 50 kcps.

Energy Technology Data Exchange (ETDEWEB)

This report covers the gamma detectors, measurement instrumentation, and testing results of a system developed at Los Alamos National Laboratory. This system monitors the process liquid waste streams at the Plutonium Facility (TA-55) for the presence of radioactive contamination. The detectors are at various points on the acid, caustic, and industrial waste lines. Two of the detectors are on the sanitary sewer lines from the facility. A custom interface unit associated with these two detectors furnishes the facility operation center with a notification of the detection of material. All of the detectors furnish measurement information to a central computer system for storage and trending.

British Library Electronic Table of Contents (United Kingdom)

The design and first results from a Double Sided Silicon Strip Detector (DSSSD) recently installed at the Lund Nuclear Microprobe facility (NMP) are presented. The detector has 64 sector strips and 32 ring strips, which in combination give more than 2000 detector cells, each with characteristics comparable with a standard surface barrier detector (SBD). The detector has been tested both with radioactive sources and with different ion beams and energies. The most striking features are the high rate virtually pile-up free operation and also the possibility of detailed measurement of angular distributions.

Energy Technology Data Exchange (ETDEWEB)

The first application of optical Stark modulation has been applied to measure spatially precise Stark-modulated IR absorption spectra in a flame.

International Nuclear Information System (INIS)

... 45 p. absorption spectroscopy errors lead lead 203 beta decay radioisotopes

CERN Document Server

Design and R&D for the forward calorimeter and silicon tracker of the $\\tau$cF detector

Energy Technology Data Exchange (ETDEWEB)

Capacitance dispersion on the fractal carbon electrode with edge and basal orientations was investigated using atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and a.c.-impedance spectroscopy. For this purpose, four types of as-received pyrolytic graphite electrode, as-received, mechanically polished, and as-activated glassy carbon electrodes were prepared with different surface irregularities and amounts of edge orientations. The apparent self-similar fractal dimensions of the carbon electrodes were determined from the analyses of AFM images based upon triangulation method. The amounts of edge orientations on the surface of the carbon electrodes were qualitatively estimated from the XPS analysis of surface acidic functional groups that were preferably formed on the edge planes by the heat treatment of the carbon electrodes. The values of the constant phase element exponent {alpha} ...

Energy Technology Data Exchange (ETDEWEB)

Here we examine Fe speciation within Fe-encrusted biofilms formed during 2-month seafloor incubations of sulfide mineral assemblages at the Main Endeavor Segment of the Juan de Fuca Ridge. The biofilms were distributed heterogeneously across the surface of the incubated sulfide and composed primarily of particles with a twisted stalk morphology resembling those produced by some aerobic Fe-oxidizing microorganisms. Our objectives were to determine the form of biofilm-associated Fe, and identify the sulfide minerals associated with microbial growth. We used micro-focused synchrotron-radiation X-ray fluorescence mapping (mu XRF), X-ray absorption spectroscopy (mu EXAFS), and X-ray diffraction (mu XRD) in conjunction with focused ion beam (FIB) sectioning, and highresolution transmission electron microscopy (HRTEM). The chemical and mineralogical composition of an Fe-encrusted biofilm was queried at different spatial scales, and the spatial relationship between primary ...

Science.gov (United States)

Applications of cutting-edge estimation techniques, such as, but not limited to, sigma-point and particle filters, to spaceflight navigation problems. ...

Science.gov (United States)

... Separation," AGARD,Rept 272, April 1960, ... Leading Edge Effect on Supersonic Boundary Layer Flow." ... of Gas Injection in Separated Flows." TCEA, ...

International Nuclear Information System (INIS)

2006 p. 43 Ukraine Beletskii, AA Grigor'eva, LI Sorokovoy, EL Chechkin, VV

CERN Document Server

Prompted by work on the buckling instability in barred spiral galaxies, much effort has been devoted lately to the study of boxy/peanut-shaped (B/PS) bulges. Here, we present new bar diagnostics for edge-on spiral galaxies based on periodic orbits calculations and hydrodynamical simulations. Both approaches provide reliable ways to identify bars and their orientations in edge-on systems. We also present the results of an observational search for bars in a large sample of edge-on spirals with and without B/PS bulges. We show that most B/PS bulges are due to the presence of a thick bar viewed edge-on while only a few may be due to accretion. This strongly supports the bar-buckling mechanism for the formation of B/PS bulges.

Science.gov (United States)

mulation, with flow quantities stored at the grid vertices. OVERFLOW ..... attack: a separation bubble near the trailing edge of the ..... AGARD CP-429, Jul. 1988. ...

International Nuclear Information System (INIS)

Carbon-14 was analysed by direct absorption of carbon dioxide on the mixture of organic amine compound and scintillation cocktail then counted by low level liquid scintillation counter. This method can be applied for radiocarbon dating. In this study, the effects of carbon dioxide absorption, and counting efficiency were investigated using various commercial available cocktail. It was found that permafluor V and Ready Gel showed the highest carbon dioxide absorption whereas the Permafluor V showed the highest counting efficiency

KoreaScience (Korea)

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KoreaScience (Korea)

Full Text Available

KoreaScience (Korea)

Full Text Available

Energy Technology Data Exchange (ETDEWEB)

This human investigation of lead absorption from the lungs utilized two forms of lead, lead chloride and lead hydroxide; the former was used in picogram amounts and the latter at microgram levels. These two species of lead were selected in an attempt to simulate the range of physicochemical properties found in atmospheric lead (urban air). Aerosols labeled with lead-203 were made of comparable aerodynamic size (MMAD 0.25 ..mu..m +- 0.1) by using sodium chloride as the deposition-determining aerosol. After brief, mouthpiece exposures, 17 subjects were followed by serial counting with a thoracic array of 12 2-in. scintillation detectors and two 2-in. leg counters, all coupled to single channel analyzers. Serial blood samples were also taken. The two exposure groups showed similar total deposition values (23 vs 26%) and the same biological retention halftimes, viz., 22.6 h. When the retention data were corrected for blood-borne /sup 203/Pb, the ...

International Nuclear Information System (INIS)

Full text: A Large Sample Neutron Activation Analysis (LSNAA) facility is under development at GRR-1 research reactor, NCSR 'Demokritos'. The LSNAA facility design incorporates sample irradiation in the reactor's graphite thermal neutron column and subsequent measurement of the activity induced at a gamma spectroscopy system with gamma ray transmission measurement options included. Monte Carlo neutron and photon transport code MCNP-4C was used to model the facility. Appropriate correction factors accounting for neutron field perturbation during sample irradiation, high purity germanium detector efficiency for the volume source and gamma ray self-absorption within the sample itself were derived. The results of the computations were experimentally verified by activation foil measurements for a set of known materials and a range of sample sizes extending up to 10 litters. Moreover, the special issue of large sample analysis of non-homogeneous ...

International Nuclear Information System (INIS)

FexZn1-x alloys were electrochemically deposited on aluminum substrates from a sulfate bath. The K?/K? x-ray intensity ratios of Zn and Fe in FexZn1-x thin films have been experimentally studied. The energy dispersive x-ray fluorescence (EDXRF) technique was used to measure K x-ray photons. Samples were excited by using 59.5 keV photons emitted by a 50 mCi 241Am radioactive source. The emitted K x-rays were detected by an Ultra-LEGe detector having a resolution of 150 eV at 5.9 keV. In addition, the effect of bath composition on the phase structure was investigated by x-ray diffraction (XRD) analysis. The composition of the thin films was analyzed by atomic absorption spectrometry analysis. Iron content was shown to strongly affect the structure of Zn-Fe alloys. It was found that the K-shell x-ray intensity ratio changed in FexZn1-x thin films for different values of x. The reason for this change may be that the electronegativity of iron is ...

International Nuclear Information System (INIS)

The detection efficiency of a lithium glass detector was calculated using MCNP code, and the calculation was compared with the published results in Pulsed Sphere Plan. A lithium glass detector of our own was made, and its neutron efficiency was calculated. The calculated neutron efficiency was verified with both pulsed and steady DD neutrons. Characteristics of Neutron response of "6Li detector was discussed. (authors)

International Nuclear Information System (INIS)

A network of second-generation low-temperature gravitational radiation detectors is nearing completion. These detectors, sensitive to mechanical strains of order 10"-"1"8, are possible because of a variety of technical innovations that have been made in cryogenics, low-noise superconducting instrumentation, and vibration isolation techniques. Another five orders of magnitude improvement in energy sensitivity of resonant-mass detectors is possible before the linear amplifier quantum limit is encountered. 33 references, 3 figures, 1 table.

International Nuclear Information System (INIS)

(1973). USSR Ovcharenko, AM Nedavnij, OI Kapranov, BI Tomskij

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared

Energy Technology Data Exchange (ETDEWEB)

A new technology called a self-aligned metal-silicide process is described in the fabrication of silicon detectors. It has been found that this technology improves both detector yield and leakage current. The use of a metal silicide also gives a lower contact resistance and, depending on the thermal process, a controllable junction depth, which may be essential in the integration of detectors and their electronics.

Energy Technology Data Exchange (ETDEWEB)

Thin film ultraviolet detectors based on hydrogenated amorphous silicon alloys are realized with different diode structures (PIN, NIP, PN, and NP). The PIN and NIP detectors exhibit higher sensitivity in the ultraviolet spectrum and a significant lower dark current in comparison to the PN or NP structures. The best detector performance was achieved with a 33 nm thick PIN diode. This detector shows a maximum of quantum efficiency of 36.3% at a wavelength of 310 nm. By varying the thickness of the semi-transparent Ag front contact the selectivity of the detectors with the quantum efficiency peak at 320 nm can be adjusted. Thus, the spectral sensitivity of the detector shifts from a broad UV to a selective UV-B spectrum. (orig.)

International Nuclear Information System (INIS)

To investigate the characteristics of a reactor and a neutron generator, a small scintillation detector with an optical fiber with ThO_2 has been developed to measure fast neutrons. However, experimental facilities where "2"3"2Th can be used are limited by regulations, and S/N ratio is low because the background counts of this detector are increase by alpha decay of "2"3"2Th. The purpose of this study is to develop a new optical fiber detector for measuring fast neutrons that does not use nuclear material such as "2"3"2Th. From the measured and calculated results, the new optical fiber detector which uses ZnS(Ag) as a converter material together with a scintillator have the highest detection efficiency among several developed detectors. It is applied for the measurement of reaction rates generated from fast neutrons; furthermore, the absolute detection efficiency of this ...

Energy Technology Data Exchange (ETDEWEB)

The chemistries of reactants, plasticizers, solvents and additives in an epoxy paint are discussed. Polyamide additives may play an important role in the absorption of molecular iodine by epoxy paints. It is recommended that the unsaturation of the polyamide additive in the epoxy cure be determined. Experimental studies of water absorption by epoxy resins are discussed. These studies show that absorption can disrupt hydrogen bonds among segments of the polymers and cause swelling of the polymer. The water absorption increases the diffusion coefficient of water within the polymer. Permanent damage to the polymer can result if water causes hydrolysis of ether linkages. Water desorption studies are recommended to ascertain how water absorption affects epoxy paint.

International Nuclear Information System (INIS)

Studies of the gastrointestinal absorption of lead-203 chloride were carried out on 11 normal subjects, 7 males and 4 females. Whole body counting of these subjects after administration of 74 kBq (2 #mu#Ci) of cyclotron-produced lead-203 chloride showed a mean absorption of 21.3% of the dose with a range from 10.4 to 47.7%. The male subjects had a lower mean absorption of 18.1% of the dose compared with a mean of 26.9% in the females. Although this difference did not reach statistical significance, it is postulated that male/female differences in absorption may relate to differences in iron saturation of the subjects.

International Nuclear Information System (INIS)

High (spatial) resolution imaging detectors for X-ray astronomy were developed. Several prototype detectors built and their feasibility and baseline performance were assessed. Two of these detector types are proposed for investigations on the advanced X-ray astrophysics facility (AXAF). The readiness of a new X-ray imaging system, the charge coupled device (CCD) imaging specctrometer is outlined, and state of the art performance parameters for microchannel plate (MCP) and CCD detectors are measured. Laboratory facilities and procedures for coating MCP are developed general high resolution imagery systems are analyzed.

Energy Technology Data Exchange (ETDEWEB)

Surface deposition probe techniques have been shown to be an effective means of determining the characteristics of the plasma edge region of magnetic confinement devices. Experimental results on ISX-B and EBT-S have led to a consistent picture of the edge plasma and the dominant impurity introduction mechanisms. This picture is supported by numerous other measurements and emphasizes the importance of concentrating several techniques on the complex problems of plasma fusion.

CERN Document Server

We give a closed formula for volumes of generic hyperbolic tetrahedra in terms of edge lengths. The cue of our formula is by the volume conjecture for the Turaev-Viro invariant of closed 3-manifolds, which is defined from the quantum 6j-symbols. This formula contains the dilogarithm functions, and we specify the adequate branch to get the actual value of the volumes.

Science.gov (United States)

The effect of velocity gradient on stagnation region heat transfer augmentation by free stream turbulence was investigated. Heat transfer was measured in the stagnation region of four models with elliptical leading edges with ratios of major to minor axes of 1:1, 1.5:1, 2.25:1, and 3:1. Four geometrically similar, square bar, square mesh, biplane grids were used to generate free stream turbulence with different intensities and length. Heat transfer measurements were made for the following ranges of parameters: Reynolds number, based on leading edge diameter, 37,000 to 228,000; dimensionless leading edge velocity gradient, 1.20 to 1.80; turbulence intensity, 1.1 to 15.9%; and length scale to leading edge diameter ratio, 0.05 to 0.30. Stagnation point heat transfer augmentation by free stream turbulence can be predicted using a modified version of a previously developed correlation for a circular leading ...

Energy Technology Data Exchange (ETDEWEB)

One of the important aspects in an absorption system is the effectiveness in which the gas and liquid phases come into contact with each other. An effective absorption process will provide sufficient contacting area for the gas and liquid phases to interact upon. With this in mind, work was conducted to evaluate carbon dioxide (CO{sub 2}) absorption into aqueous solutions of monoethanolamine (MEA) using two different types of contacting devices: gas absorption membrane (GAM) modules and traditional packed columns. The performance of these two absorption devices was compared to one another using the overall mass transfer coefficient (K{sub G}a{sub v}) as a basis. The GAM module contained microporous polypropylene hollow fibre membranes and the packed absorption column contained Sulzer DX structured packing. The results indicate that GAM modules tend to have ...

Energy Technology Data Exchange (ETDEWEB)

The absorption of carbonyl sulfide in aqueous methyldiethanolamine (MDEA) was studied over a range of temperatures and MDEA concentrations. MDEA is commonly used for selective absorption of hydrogen sulfide in the presence of carbon dioxide. However, sulfur in the form of COS may also be present and it is necessary that estimates of absorption rates of this compound be made. The objective of this study is to determine the physiochemical properties needed to predict COS absorption rates in aqueous MDEA. Free gas solubility and the diffusivity of COS in MDEA solutions were measured over the temperature range 15 to 40{sup 0}C for MDEA concentrations up to 30 weight per cent using the nitrous oxide analogy method. Solubilities were measured volumetrically in an equilibrium cell and diffusivities were measured using a laminar liquid jet absorber. The kinetics of the reaction between COS and MDEA were studied ...

Science.gov (United States)

Up to the present, the generic values of the Common cause failure (CCF) event parameters have been used in most PSA projects for the Korean NPPs. However, the CCF analysis should be performed with plant specific information to meet Category II of the ASME PRA Standard. Therefore, we estimated the Alpha factor parameters of the emergency diesel generator (EDG) for Ulchin Unit 3 by using the International Common-Cause Failure data Exchange (ICDE) database. The ICDE database provides the member countries with only the information needed for an estimation of the CCF parameters. The Ulchin Unit A3, pressurized water reactor, has two onsite EDGs and one alternate AC (AAC) diesel generator. The onsite EDGs of Unit 3 and 4 and the AAC are manufactured by the same company, but they are designed differently. The estimation procedure of the Alpha factor used in this study follows the approach of the NUREG/CR-5485. Since we did not ...

International Nuclear Information System (INIS)

Full text: Pigments possessing the ability to confer high solar reflectance have received considerable attention in recent years. The inorganic class of NIR reflective pigments are mainly metal oxides and are primarily employed in two applications: (i) visual camouflage and (ii) reducing heat build up. More than half of the solar radiation consists of near-infrared radiation (52%), the remaining being 43% visible light and 5% ultraviolet radiation. Over heating due to solar radiation negatively affects comfort in the built environment and contributes substantially to electrical consumption for air conditioning and release of green house gases. A pigment which has strong reflections in the NIR region (780-2500 nm) can be referred to as a 'cool' pigment. However, most of the NIR reflective inorganic pigments particularly yellow (eg. cadmium yellow, lead chromate, chrome titanate yellow etc.) contain toxic metals and hence their consumption is being limited. Replacing them with ...

UK PubMed Central (United Kingdom)

A retrospective study of the relationship of season to the absorption of radiolead in laboratory rats was performed using data representing 305 animals from 36 experiments over 6 calendar years. Male...Full Text Available

International Nuclear Information System (INIS)

A liquid column was used for the experiments reported in Part 1. However, it only gives the observation of the effect of fast reaction because the liquid flow was controlled to uniform laminar flow and the contact is limited to short time of around 10 ms. In practical absorbing operation, turbulence is involved in liquid flow, and the residence time for contact is long. Hence, the absorption of trace iodine in the purified air has been experimented by using a constant interface area type stirred absorption tank. Prior to the experiment, the characteristics of the absorption tank was investigated by conducting pure carbon dioxide absorption test with purified water. It gave the conclusion that the tank was sufficiently usable for fundamental researches. In short contact time absorption, the iodine dissolved and absorbed in liquid phase is affected by reaction of hypoiodous acid and ...

UK PubMed Central (United Kingdom)

1. Rates and rate coefficients of glucose utilization and replacement in post-absorptive rats, either conscious or under halothane anaesthesia, were determined in a thermoneutral environment by using...Full Text Available

Science.gov (United States)

The vibrational states, absorption energies, and diffusions of H in Pd and Pd1-xAgx(0Pd-Ag alloys should avoid the Ag-rich areas.

Science.gov (United States)

In this paper, we introduce a new recursive neural network model able to process directed acyclic graphs with labelled edges. The model uses a state transition function which considers the edge labels and is independent both from the number and the order of the children of each node. The computational capabilities of the new recursive architecture are assessed. Moreover, in order to test the proposed architecture on a practical challenging application, the problem of object detection in images is also addressed. In fact, the localization of target objects is a preliminary step in any recognition system. The proposed technique is general and can be applied in different detection systems, since it does not exploit any a priori knowledge on the particular problem. Some experiments on face detection, carried out on scenes acquired by an indoor camera, are reported, showing very promising results. PMID:16181770

British Library Electronic Table of Contents (United Kingdom)

In this study, we thoroughly analyzed abrupt behaviors, trends, and periodicity properties of water vapor flux and moisture budget entering and exiting the four edges of the Pearl River basin based on the NCAR/NCEP reanalysis dataset by using the continuous wavelet transform and the simple two-phase linear regression technique. Possible implications for hydrological cycle and water resource management of these changes are also discussed. The results indicate that: (1) the water vapor propagating through the four edges of the Pearl River basin is decreasing, and it is particularly true for the changes of the water vapor flux exiting from the north edge of the study river basin. The transition point from increase to decrease occurs in the early 1960s; (2) The wavelet transform spectra indica...

UK PubMed Central (United Kingdom)

An ultrasensitive laser-induced fluorescence detector was used with capillary electrophoresis for the study of 5-carboxy-tetramethylrhodamine. The raw signal from the detector provided roughly...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The most important developments in gaseous detectors at LNL are reviewed. Some aspects of timing, pulse height and position resolutions of avalanche counters are reported. The experimental work on heavy-ion identification by Bragg curve spectroscopy is summarized.

Energy Technology Data Exchange (ETDEWEB)

An analyser for detecting explosives has at least one neutron source and a plurality of gamma ray detectors. An article to be analysed is moved adjacent the source and detectors and is subjected to neutrons which generate gamma rays from any nitrogen in the article. The gamma rays are detected and analysed to determine the nitrogen concentration within the article. In order to achieve an area of uniform detection there are a plurality of detectors equidistant both from the or each source and from the article to be analysed. In order to avoid a decrease in sensitivity away from the source(s) and detectors there may be a second opposing array of source(s) and detectors on the opposite side of the article. For greatest uniformity of detection, a source in one array opposes a detector in the other array and vice versa. Transmission of radiation from the analyser is ...

UK PubMed Central (United Kingdom)

We report on a high resolution, monolithic crystal PET detector design concept that provides depth of interaction (DOI) positioning within the crystal. Our design utilizes a novel sensor on...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

In this note it is suggested that binuclear platinum(II) complexes with a solely inorganic bridging pyrophosphito ligand also possess many of the complementary advantages of inorganic and organic dyes. They are evaluated for their potential use as a luminescent solar concentrator material. The disadvantages include: the high cost of platinum; the absorption spectra in solution shows a weaker absorption at 452 nm which may cause reabsorption of emitted light; the positions of the absorption and emission maxima are not at the optimal wavelengths for absorption of sunlight and emission to a solar cell. In spite of these drawbacks the author believes the platinum complexes merit consideration for fabrication of solar concentrator devices.

Science.gov (United States)

... significant change of spontaneous radiation intensity. It is very sensitive technique allowing the observation of small changes of light absorption. ...

International Nuclear Information System (INIS)

Rats and guinea pigs were fed "2"3"8Pu either biologically incorporated into alfalfa (by growth of the plant on soil containing Pu) or added as a solution to alfalfa, or were gavaged with a Pu solution. Depending upon the plant material fed, there appeared to be a twofold increase in "2"3"8Pu-gut absorption by the rat and a two- to fourfold increase in the guinea pig as compared with absorption from the Pu solution. The data, though limited and variable, suggest that Pu bound to plant tissue may have higher gut absorptivity than inorganic Pu in both herbivorous and nonherbivorous rodents.

Science.gov (United States)

... The data were transformed into total hemispherical emittance values and correlated with respect to ceramic coating thickness and temperature ...

Science.gov (United States)

... energy absorption characteristics of composite sandwich panels, thermoplastic energy-absorbing subfloor structures, and shoulder belt pre- tensioners. ...

International Nuclear Information System (INIS)

English 2009 p. 79 Ukraine Brudgam, M. Lauber, Ph. Garcia Munoz, M.

International Nuclear Information System (INIS)

This work reports on the use of three state-of-the-art Monte Carlo codes (MCNPX, PENELOPE, FLUKA) in the efficiency calibration of a Broad-Energy Germanium (BEGe) detector. Initial discrepancies found between the experimental and computational efficiency values are related to the poor knowledge of some physical parameters of the detector (dead-layers, crystal dimensions, etc.). As a consequence, a sensitivity analysis was carried out. Each parameter was systematically analyzed, and an accurate model of the detector was determined. The obtained results are consistent, allowing this model to be used in computational efficiency calibrations of the equipment at stake.

Science.gov (United States)

We report on the results of a preliminary study of the GCR-induced photon luminescence of the Moon

International Nuclear Information System (INIS)

(Apr 1974). Japan Murakami, Akira . Saga Univ. (Japan). Dept. of

International Nuclear Information System (INIS)

We report on recent measurements with Thick GEM-like (THGEM)-based imaging detectors. The THGEM is a robust gaseous electron multiplier similar to GEM but with larger dimensions. It has high electron multiplication, of 105 and 107 in single- and double-THGEM structure, respectively, fast signals and ?10MHz/mm2 counting rate capability. It can be produced in any shape and over large area. In view of many possible applications of THGEM-based imaging detectors, in particle physics and beyond, we have recently studied the localization properties of a 2D 10x10cm2 detector. The results of these studies are presented.

Science.gov (United States)

Spectral absorption properties of total suspended matter (TSM) and colored dissolved organic matter (CDOM) are important for the use of the bio-optical model to estimate water quality parameters. This study aims to investigate the variation in the absorption coefficients of TSM and CDOM of inland waters. A total of 92 water samples were collected from Shitoukoumen Reservoir and Songhua Lake in Northeast China, analyzed for TSM and Chl-a, and measured for the absorption coefficient of TSM, CDOM and total pigments using a laboratory spectrophotometer. The absorption coefficient of TSM has been decomposed for phytoplankton and inorganic sediments. The results show that for Shitoukoumen Reservoir, CDOM has strong absorptions with shallow absorption slopes (i.e., the coefficient S in a(?)=a(?0)exp[-S(?- ?0)]) and large absorption at 355 nm; and ...

Energy Technology Data Exchange (ETDEWEB)

The development of a gas-operated diffusion absorption heat pump for the heating of living spaces is described. By various improvement an energy efficiency of the prototypes of 1.5 was achieved. Structural alterations led to a lower overall height and lower production costs. The CFCs used in electric heat pumps were replaced by environmentally neutral ammonia. Compared with conventional gas heating systems, the CO2 output could be reduced by more than 30%. figs., tabs.

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An equation is described to estimate the value of the liquid-phase mass-transfer coefficient of aqueous solutions of surfactants from its value for pure water. The form of the equation is obtained from Levich's theory, and it is adjusted to experiments of absorption of CO/sub 2/ in aqueous solutions of five pure surfactants. The reduction of the absorption rate is correlated with the interfacial pressure of the solution.

Science.gov (United States)

The report gives results of a pilot-plant study of the ammonia absorption/ammonium bisulfate regeneration process for removing SO2 from the stack gas of coal-fired power plants. Data were developed on the effects of such operating variable in the absorption of SO2 by ammoniacal l...

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Superconducting thin film particle detectors can be very attractive due to the low sensitivity to radiation damage. We describe the fabrication procedure and the characterization of Nb/Al bilayers as particle detectors. First steady and dynamical results are reported from tests of 5 MeV alpha-particle detection.

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The upgraded CDF II detector has collected first data during the initial operation of the Tevatron accelerator in Run II. The simulation of the CDF electromagnetic and hadronic central and upgraded plug (forward) calorimeter is based on the Gflash calorimeter parameterization package used within the GEANT based detector simulation of the Run II CDF detector. We present the results of tuning the central and plug calorimeter response to test beam data.

CERN Document Server

A study on the aging process of gas detectors was presented. How the development of more performing but delicate detectors, the use of faster but aggressive gases, and the need to cover large areas, led to unexpected problems was discussed. Various methods for curing aged detectors were also highlighted. (Edited abstract) 37 Refs.

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Ionization counters employing Bragg curve spectroscopy have been constructed for use in a 4{pi} geometry. These detectors compare very favorably in terms of both energy and charge resolution with small solid angle devices. These detectors have a large dynamic range because they are backed by scintillation detectors, and are thus capable of detecting and identifying particles with energies from 1 MeV/nucleon up to 200 MeV/nucleon. (orig.).

International Nuclear Information System (INIS)

There is significant interest in using computed tomography (CT) for in vivo imaging applications in mouse models of disease. Most commercially available mouse x-ray CT scanners utilize a charge-coupled device (CCD) detector coupled via fibre optic taper to a phosphor screen. However, there has been little research to determine if this is the optimum detector for the specific task of in vivo mouse imaging. To investigate this issue, we have evaluated four detectors, including an amorphous selenium (a-Se) detector, an amorphous silicon (a-Si) detector with a gadolinium oxysulphide (GOS) screen, a CCD with a 3:1 fibre taper and a GOS screen, and a CCD with a 2:1 fibre taper and both GOS and thallium-doped caesium iodide (CsI:Tl) screens. The detectors were evaluated by measuring the modulation transfer function (MTF), noise power spectrum (NPS), detective quantum ...

UK PubMed Central (United Kingdom)

Autophagy is a ubiquitous catabolic process that ensures organism’s well-being by sequestering a wide array of undesired intracellular constituents into double-membrane vesicles termed...Full Text Available

UK PubMed Central (United Kingdom)

Most insects are thought to fly by creating a leading-edge vortex that remains attached to the wing as it translates through a stroke. In the species examined so far, stroke amplitude is large, and...Full Text Available

International Nuclear Information System (INIS)

In this article are presented main results on electric potential investigations in stellarator/torsatron TJ-II and tokamak T-10 in a comparable regimes of device operation.

Science.gov (United States)

We present an x-ray magnetic circular dichroism (XMCD) study performed on both Ho{sub 6}Fe{sub 23} and Y{sub 6}Fe{sub 23} compounds as a function of the temperature. The combined analysis of both Fe K-edge and Ho L{sub 2,3}-edge XMCD spectra recorded through the magnetic compensation transition allows us to disentangle the thermal dependence of both Fe and Ho magnetic moments in Ho{sub 6}Fe{sub 23}. In addition, contributions from Ho ions to the Fe K-edge XMCD signals and, conversely, from Fe ions to the Ho L{sub 2,3}-edge XMCD spectra have been clearly identified. These extra contributions, arising from the strong Fe(3d)-Ho(5d) hybridization, have been isolated from the spectra and correlated with the magnetic state of both Ho and Fe ions surrounding the absorbing site. The influence of these contributions to the values of the orbital and spin moments derived by using sum rule analysis is also shown.

Energy Technology Data Exchange (ETDEWEB)

Semiconductor nanocrystals smaller than the bulk exciton show substantial quantum confinement effects. Recent experiments including Stark effect, resonance Raman, valence band photoemission, and near edge X-ray adsorption will be used to put together a picture of the nanocrystal electronic states.

CERN Document Server

Present in over 45% of local spirals, boxy and peanut-shaped bulges are generally interpreted as edge-on bars and may represent a key phase in the evolution of bulges. Aiming to test such claims, the kinematic properties of self-consistent 3D N-body simulations of bar-unstable disks are studied. Using Gauss-Hermite polynomials to describe the stellar kinematics, a number of characteristic bar signatures are identified in edge-on disks: 1) a major-axis light profile with a quasi-exponential central peak and a plateau at moderate radii (Freeman Type II profile); 2) a ``double-hump'' rotation curve; 3) a sometime flat central velocity dispersion peak with a plateau at moderate radii and occasional local central minimum and secondary peak; 4) an h3-V correlation over the projected bar length. All those kinematic features are spatially correlated and can easily be understood from the orbital structure of barred disks. They thus provide a reliable ...

UK PubMed Central (United Kingdom)

BackgroundNetwork visualization would serve as a useful first step for analysis. However, current graph layout algorithms for biological pathways are insensitive to biologically...Full Text Available

CERN Document Server

In Graph Theory a number of results were devoted to studying the computational complexity of the number modulo 2 of a graph's edge set decompositions of various kinds, first of all including its Hamiltonian decompositions, as well as the number modulo 2 of, say, Hamiltonian cycles/paths etc. While the problems of finding a Hamiltonian decomposition and Hamiltonian cycle are NP-complete, counting these objects modulo 2 in polynomial time is yet possible for certain types of regular undirected graphs. Some of the most known examples are the theorems about the existence of an even number of Hamiltonian decompositions in a 4-regular graph and an even number of such decompositions where two given edges e and g belong to different cycles (Thomason, 1978), as well as an even number of Hamiltonian cycles passing through any given edge in a regular odd-degreed graph (Smith's theorem). The present article introduces a new algebraic ...

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The problems in computer vision range from edge detection and segmentation at the lowest level to the problem of cognition at the highest level. This correspondence describes the organization and operation of a semantic network array processor (SNAP) as applicable to high level computer vision problems. The architecture consists of an array of identical cells each containing a content addressable memory, microprogram control, and a communication unit. The applications discussed in this paper are the two general techniques, discrete relaxation and dynamic programming. While the discrete relaxation is discussed with reference to scene labeling and edge interpretation, the dynamic programming is tuned for stereo.

International Nuclear Information System (INIS)

The first successful application of a new method to investigate phase transformations in real time, like the decomposition of austenite into bainite in grey iron, is described. During the ongoing transformation, transmission spectra of thermal neutrons, which contain Bragg edges corresponding to the crystal structure of the transforming phases, are recorded. By evaluating the height of these Bragg edges, which is a measure of the volume fraction of the phase, at different transformation times, the transformation can be followed in-situ in a time resolved manner. The method is compared to other previously used methods (micrographs, dilatometry, diffraction techniques); also a summary and an outlook are given. ((orig.)).

CERN Document Server

A fundamental and very well studied region of the Erd\\"os-R\\'enyi process is the phase transition at n/2 edges in which a giant component suddenly appears. We examine the process beginning with an initial graph. We further examine the Bohman-Frieze process in which edges between isolated vertices are more likely. While the positions of the phase transitions vary, the three processes belong, roughly speaking, to the same universality class. In particular, the growth of the giant component in the barely supercritical region is linear in all cases.

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Measurements of the expansion rate of pure-electron plasmas have been performed on the Electron Diffusion Gauge (EDG) device at background helium gas pressures in the 5 x 10(superscript -8) Torr to 1 x 10(superscript -5) Torr range, where plasma expansion due to electron-neutral collisions dominates over plasma expansion due to trap asymmetries. It is found that the expansion rate, defined as the time rate of change of the particles' mean-square radius, scales approximately linearly with pressure and inversely as the square of the magnetic field strength in this regime, in agreement with classical predictions.

CERN Document Server

A complex network approach on a rough fracture is developed. In this manner, some hidden metric spaces (similarity measurements) between apertures profiles are set up and a general evolutionary network in two directions (in parallel and perpendicular to the shear direction) is constructed. Also, an algorithm (COmplex Networks on Apertures: CONA) is proposed in which evolving of a network is accomplished using preferential detachments and attachments of edges (based on a competition and game manner) while the number of nodes is fixed. Also, evolving of clustering coefficients and number of edges display similar patterns as well as are appeared in shear stress, hydraulic conductivity and dilation changes, which can be engaged to estimate shear strength distribution of asperities.

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An anaerobic fermenter-decanter for the purification of residual water from the sugar industry, with recovery of methane, consists of a tank with inclined walls, with a central agitator on a vertical shaft. A flexible cover anchored by its periphery to the walls of the tank and totally submerged forms a collecting pocket for the fermentation gases. The water to be purified is introduced, after being heated to about 35, towards the bottom of the tank near the agitator. A metal collecting bell with submerged edges and with the shaft of the agitator passing axially through it is connected by its edges to a central opening of the cover. The purification yields may exceed 90%.

British Library Electronic Table of Contents (United Kingdom)

Gastrointestinal patches represent a novel multiparticulate drug delivery system able to increase the intestinal absorption of drugs with poor bioavailability. The number of patches to administer is a critical issue since it is related to the surface and drug concentration at the absorption site. The objective of this article is to evaluate the effect of the number of administered patches on the final absorption of leuprolide, a peptide chosen as model drug, assuming complete adhesion of all the devices to the intestinal membrane. The same dose of leuprolide was encapsulated into 2, 4 and 6 patches; the resulting intestinal absorption profiles were measured with the Ussing chamber ex vivo experimental setup and compared between them. The results showed that varying the number of patches, t...

International Nuclear Information System (INIS)

An imaging position sensitive detector for charged particles, neutrons, X-and gamma rays has been developed. The novel feature of this scintillation imaging radiation detector is its ability to detect individual nuclear particle scintillations with a h igh degree of spatial resolution. The key elements of this detector system are a high gain, low noise image intensifier tube, a CCD camera and commercially available image processing hardware and software. This detector system is highly effective for applications such as low fluence and real time neutron radiography, mapping of radioactive contamination in nuclear reactor fuel rods, X-ray diffraction imaging, high speed autoradiography and in general position sensitive detection of nuclear radiation. Results of some of the exploratory experiments carried out using this detector system are presented in this paper. (orig.).

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Solid state nuclear track detectors (SSNTD) are widely used for radon measurements and CR-39 is one of the most popular SSNTD. In this work it was determined the calibration factor for radon concentration measurements through the passive method with CR-39 detectors. The detectors were put in a proper device (an adapted Lucas cell) and exposed to the standard radon concentration through the Pylon Model RN-150 flow through radon gas source. After exposure, the detectors were etched for 5.5 hours in a KOH solution at 80 deg C in a bath at a constant temperature. The track density was read in an Axiolab-Zeiss optical microscope, with nominal magnification of X10 connected to a video camera and to a personal computer. The calibration factor was obtained through the relation between standard radon concentration, track density and exposure time. (author)

British Library Electronic Table of Contents (United Kingdom)

Summary Solid state nuclear track detectors are used to determine the concentration of a particles in the environment. The standard method for assessing exposed detectors involves 2D image analysis. However 3D imaging has the potential to provide additional information relating to angle as well as to differentiate clustered hit sequences and possibly energy of a particles but this could be time consuming. Here we describe a new method for rapid high-resolution 3D imaging of solid state nuclear track detectors. A `LEXT' OLS3100 confocal laser scanning microscope (Olympus Corporation, Tokyo, Japan) was used in confocal mode to successfully obtain 3D image data on four CR-39 plastic detectors. Three-dimensional visualization and image analysis enabled characterization of track features. This ...

International Nuclear Information System (INIS)

A large area Bragg curve spectroscopy (BCS) detector and a position sensitive parallel grid avalanche counter have been developed to study heavy ion reactions, such as inelastic excitations and few nucleon transfer reactions near the Coulomb barrier. Reasonably good resolutions have been achieved for energy, atomic number and angle. A theoretical investigation on the mass dependence of the Bragg peak signal from the BCS detector, shows that there is a negligible mass dependence related to the geometry of the detector. The mass number of the heavy ions which cannot be obtained by the above method, has been identified by detecting the corresponding characteristic gamma rays from the product nuclei with two large solid angle gamma ray detectors. (orig.).

International Nuclear Information System (INIS)

A large acceptance, high stopping power, Bragg curve spectrometer has been developed for use in coincidence experiments with heavy ions. The electron collection fields are radial and position information is obtained from a resistive anode. The detector is 60 cm deep and operates at pressures of up to 2.5 atm of P-10 gas. It is mated to a scattering chamber which allows it to be moved out of plane during coincidence measurements. The detector design was aided by the results of computer simulations of the electron collection process in the detector, and of the signal processing in the electronics. The signals from the Bragg curve spectrometer are recorded in a waveform digitizer and the Bragg peak height, range, position and pileup rejection information are determined from software analysis of the recorded signals. Factors limiting the performance of the detector are discussed, and results obtained with ...

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Abstract - We have designed, built, and tested a 2-D pixellated thermal neutron detector. The detector is modeled after the MicroMegas-type structure previously published for collider-type experiments. The detector consists of a 4X4 square array of 1 cm 2 pixels each of which is connected to an individual preamplifier-shaper-data acquisition system. The neutron converter is a 10B film on an aluminum substrate. We describe the construction of the detector and the test results utilizing 252Cf sources in Lucite to thermalize the neutrons.Drift electrode (Aluminum) Converter (10B) 3 mm Conversion gap neutron (-900 V)

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Large area, single-element Si(Li) detectors have been fabricated using a novel geometry which yields detectors with reduced capacitance and hence reduced noise at short amplifier pulse-processing times. A typical device employing the new geometry with a thickness of 6 mm and an active area of 175 mm 2 has a capacitance of only 0.5 pf, compared to 2.9 pf for a conventional planar device with equivalent dimensions. These new low capacitance detectors, used in conjunction with low capacitance field effect transistors, will result in x-ray spectrometers capable of operating at very high count rates while still maintaining excellent energy resolution. The spectral response of the low capacitance detectors to a wide range of x-ray energies at 80 K is comparable to typical state-of-the-art conventional Si(Li) devices. In addition to their low capacitance, the new devices offer other advantages over ...

Science.gov (United States)

The spectral dependences of absorption photoinduced in a pure bismuth titanium oxide crystal by 532-nm laser pulses are studied. It is shown that optical absorption in the crystal in the range from 492 to 840 nm increases with increasing exposure. The photoinduced absorption relaxes in the dark for more than 60 hours. A model of photoinduced absorption is proposed which assumes the population of two trap centres with the normal energy distribution law for the concentrations of electrons photoexcited from donors to the conduction band. This model well describes the spectral dependences of photoinduced absorption by using the average ionisation energies of the traps E{sub 1} = 1.60 eV and E{sub 2} = 2.57 eV. The model is used to estimate the increase in the photorefractive sensitivity of a bismuth titanium oxide crystal in the near IR region, which was earlier observed after exposing ...

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Three typical Japanese coals of non-coking coal, coking coal and anthracite were heat-treated with KOH, and change in their pore structure was examined by absorption of N2, X-ray diffraction and TEM observation. In addition, the relation between a coal rank and pore structure was also studied by absorption experiment of N2. In experiment, the mixture of coal and KOH in a nickel holder was heat-treated in N2 gas flow at heating rate of 2{degree}C/min, and held at a fixed temperature for one hour. To clarify the pore structure, N2 absorption isotherms were measured at -196{degree}C under nearly 76cmHg using a commercially available full-automatic absorption measurement equipment. Based on the X-ray diffraction and TEM observation results on activated coals, the relation between the N2 absorption and pore structure was studied. The results are summarized as follows: (1) The yield and ...

CERN Document Server

High pressure xenon ionization chamber detectors are possible alternatives to traditional thallium doped sodium iodide (NaI(Tl)) and hyperpure germanium as gamma spectrometers in certain applications. Xenon detectors incorporating a Frisch grid exhibit energy resolutions comparable to cadmium/zinc/telluride (CZT) (e.g. 2% (at) 662keV) but with far greater sensitive volumes. The Frisch grid reduces the position dependence of the anode pulse risetimes, but it also increases the detector vibration sensitivity, anode capacitance, voltage requirements and mechanical complexity. We have been investigating the possibility of eliminating the grid electrode in high-pressure xenon detectors and preserving the high energy resolution using electronic risetime compensation methods. A two-electrode cylindrical high pressure xenon gamma detector coupled to time-to-amplitude conversion electronics ...

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APEX (ATLAS Positron EXperiment), a collaborative effort of ANL, FSU, MSU/NSCL, Princeton, Queen`s, Rochester, Washington and Yale, is an experiment to study positron and electron production in very heavy ion collisions. The electrons and positrons are detected with two detector arrays, each consisting of 216 1 mm thick Si PIN diodes, and their energy and time-of-flight are measured. The number of detectors and limited space made it necessary to develop a system that could efficiently process and transfer signals from the detectors to the charge sensing ADC`s and data readout electronics as well as monitor the condition of the detectors. The discussion will cover the electronics designed for the Si detectors, including the charge amplifier, ``Mother board`` for the charge amplifiers, 8 channel Shaper, 16 channel Constant Fraction Discriminator (CFD), 16 channel Peak-to-FERA (PTF) ...

International Nuclear Information System (INIS)

Neutron semiconductor detectors for neutron counting and neutron radiography have an increasing importance. Simple silicon neutron detectors are combination of a planar diode with a layer of an appropriate neutron converter such as 6LiF. These devices have limited detection efficiency of not more than 5%. The detection efficiency can be increased by creating a 3D microstructure of dips, trenches or pores in the detector and filling it with a neutron converter. The first results related to the development of such devices are presented. Silicon detectors were fabricated with pyramidal dips on the surface covered with 6LiF and then irradiated by thermal neutrons. Pulse height spectra of the energy deposited in the sensitive volume were compared with simulations. The detection efficiency of these devices was about 6.3%. Samples with different column sizes were fabricated to study the electrical properties ...

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Theoretical development for temperature measurements via narrow line, infrared absorption of carbon dioxide (CO{sub 2}) is presented. The proposed technique is based on rapid-scanning of two adjacent absorption line shapes. Spectroscopic considerations for sensitivity to temperature measurements are discussed. Several line pairs are evaluated, and the R(58) and R(60) transitions of the (00{sup 0}1){l_arrow}(00{sup 0}0) band are suggested for use in high temperature measurements for combustion systems.

Energy Technology Data Exchange (ETDEWEB)

Absorption with aqueous amine solvents is at present the most viable technology for CO{sub 2} capture. While this is a proven technology, efforts are ongoing to improve it in order to make it a more attractive technology for large scale use to reduce CO{sub 2} emissions. Finding solvents with better properties is one approach to improving the technology. In this thesis methods in computational chemistry are used to improve the understanding of the chemistry of CO{sub 2} absorption in amine-water systems. The work is also intended to provide models that can be used to predict the performance of new solvents. Such predictive models are intended to facilitate the screening for new solvents

International Nuclear Information System (INIS)

The Daya Bay reactor neutrino experiment is located at the Daya Bay nuclear power plant in Shenzhen, China. The experiment deploys eight 'identical' antineutrino detectors to measure antineutrino fluxes from six 2.9 GWth reactor cores in three underground experimental halls at different distances. The target zone of the Daya Bay detector is filled with 20 t 0.1% Gd doped LAB liquid scintillator. The baseline uncorrelated detector uncertainty is ?0.38% using current experimental techniques. Daya Bay can reach a sensitivity of sin22?13<0.01 with baseline uncertainties after 3 years of data taking.

International Nuclear Information System (INIS)

We studied the niobium re-entrant cavity utilized by the Australian group in the Niobe gravitational wave detector. Instead of using their non-contact re-entrant cavity, we plan to change it to a closed one to be used in the parametric transducers of the Brazilian Mario Schenberg detector. The performance of the transducer depends on some cavity parameters such as the electrical Q and the electrical coupling. We measured the resonant frequency and the loaded electrical Q as a function of the probe position in a closed niobium #approx#15 GHz cavity operating at 4.2 K.

Energy Technology Data Exchange (ETDEWEB)

A black neutron detector of novel design has been constructed and tested as a neutron flux monitor. The neutron time-of-flight (TOF) technique was used to measure the zero degree neutron spectrum from a subnanosecond pulsed proton beam on a thick metallic lithium target. We describe the detector, discuss the shielding arrangement and electronics, determine the low-energy cut-off. We calculate the efficiency, show spectra and compare measured zero degree differential cross-section of the {sup 7}Li(p, n{sub 0}){sup 7}Be reaction with recommended published cross-sections. (orig.).

Energy Technology Data Exchange (ETDEWEB)

Long-Range Alpha Detector (LRAD) systems are designed to monitor alpha contamination by measuring the number of ions in the air. Alpha particles are a form of ionizing radiation and a typical 5-MeV alpha particle will create about 150,000 ion pairs in air. Field tests at various DOE sites have shown that LRAD Surface Soil Monitors (SSM), Sample Monitors, and Object Monitors are faster and more sensitive than traditional alpha detectors for measuring alpha contamination. This paper discusses the various applications of LRAD technology to low-level radioactive waste management.

International Nuclear Information System (INIS)

A large acceptance, high stopping power Bragg curve spectrometer has been developed for use in coincidence experiments with heavy ions. The electron collection fields are radial and position information is obtained from a resistive anode. The detector is 60 cm deep and operates at pressures of up to 2.5 atm of P-10 gas. It is mated to a scattering chamber which allows it to be moved out of plane during coincidence measurements. Factors affecting the performance of the detector are discussed, and results obtained with the detector are presented. (orig.).

Science.gov (United States)

... Values of absorption maxima, X.nax, and associated molar extinction coefficients, c, as well as values of the n-octanol/water partition coefficient( ...

International Nuclear Information System (INIS)

Available in abstract form only. Full text of publication follows: In this study. simulation of carbon dioxide absorption by Sodium Hydroxide solution in a packed bed has been investigated. At first, mass and energy balances were applied around a differential height of the bed. So, the governing equations were obtained. Surface renewal theory by Danckwerts was used to represent the mass transfer operation Finally, by changing the operating parameters like solvent temperature, inlet gas composition pressure and height of the bed, the effect of these parameters on the absorption and the composition of carbon dioxide in exit stream have been investigated. (authors)

Energy Technology Data Exchange (ETDEWEB)

Application of an optimization technique to extract the non-ideal parameters of gas absorption with chemical reactions process was described. The gas absorption was modeled using mass transfer theory to represent the realistic behaviors of an absorber. The model was a highly non-linear iterative model which correlated the overall rate of absorption as the function of unknown non-ideal parameters, including the physical liquid mass transfer coefficient and the wetted interfacial area of of packings. The optimization program was developed to minimize the sum of squares of relative errors between the model predictions and the experimental data. Four sets of experimental data (case studies) with different operating conditions were used for extracting parameters. Comparisons between predicted and experimental measured overall absorption rate were in good agreement, average absolute value of relative errors ...

Science.gov (United States)

in early 1992 from Lord Corporation, were also found. For both the reflective and absorptive polyurethanes, the fresh paint fluoresces significantly ...

International Nuclear Information System (INIS)

... School of Plant Biology. v. 23(2) p. 316-322. carbon dioxide absorption carbon

International Nuclear Information System (INIS)

Deferoxamine (DFA) (250 mg/kg), orally administered to rats, decreased Pu absorption from orally administered "2"3"8Pu(NO_3)_4 by about 1/3. The calcium salt of diethylenetriaminepentaacetic acid (Ca-DTPA), given orally 5 to 10 min after the Pu, increased absorption about four times. DFA given 10 min before the DTPA decreased the effect of the latter by a factor of two. Deferoxamine administration prior to inhalation treatment of man with DTPA may be one way to decrease possible DTPA-enhanced gut absorption of Pu.

KoreaScience (Korea)

Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The transfer of /sup 203/Pb and/or /sup 47/Ca across the intestinal epithelium of the chick was investigated, with emphasis given to the functional role of cholecalciferol (vitamin D-3). /sup 203/Pb, after introduction in the intestinal lumen, is rapidly accumulated by the intestinal tissue, and only a fraction of /sup 203/ Pb is translocated parenterally (absorbed). Cholecalciferol did not significantly affect the accumulation of /sup 203/Pb by intestinal tissue but did accelerate /sup 203/Pb movement across the basal-lateral membrane. In contrast, cholecalciferol both decreased /sup 47/Ca tissue levels and increased /sup 47/Ca absorption. In rachitic chicks, the rate of absorption of /sup 203/Pb was greater in the distal than in the proximal segments of the intestine; after cholecalciferol repletion, the degree of absorption in all segments was similar, indicating the order of cholecalciferol effectiveness as duodenum ...

Energy Technology Data Exchange (ETDEWEB)

The significant and rapid reduction of greenhouse gas emissions is recognized as necessary to mitigate the potential climate effects from global warming. The postcombustion capture (PCC) and storage of carbon dioxide (CO{sub 2}) produced from the use of fossil fuels for electricity generation is a key technology needed to achieve these reductions. The most mature technology for CO{sub 2} capture is reversible chemical absorption into an aqueous amine solution. In this study the results from measurements of the CO{sub 2} absorption capacity of aqueous amine solutions for 76 different amines are presented. Measurements were made using both a novel isothermal gravimetric analysis (IGA) method and a traditional absorption apparatus. Seven amines, consisting of one primary, three secondary, and three tertiary amines, were identified as exhibiting outstanding absorption capacities. Most have a number of ...

UK PubMed Central (United Kingdom)

Aerosol particles are ubiquitous in the troposphere and exert an important influence on global climate and the environment. They affect climate through scattering, transmission, and absorption of...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The bulk removal of CO/sub 2/ from industrial gases is a frequently applied process in the field of gas-treating. Usually chemical solvents are used in order to increase both the solvent-loading capacity and the absorption rate. These solvents often are aqueous solutions of alkanolamines. The loaded-liquid is regenerated at high temperatures with the aid steam. In the present study absorption rates are experimentally determined in various mixtures of amines over a wide range of concentrations. Simultaneously, a model was developed for the description of mass transfer accompanied by parallel reversible chemical reactions. The equations of this mass transfer model could not be solved analytically and therefore numerical techniques were used to obtain an exact description of this process. This model also includes the asymptotic situations of homogeneous catalysts and shuttle mechanism for which in the literature several approximate solutions have ...

Science.gov (United States)

Jan 13, 2011 ... This 360-degree mosaic of images from the navigation camera on ... The Radiation Assessment Detector, shown prior to its September 2010 ...

Energy Technology Data Exchange (ETDEWEB)

The intermediate silicon layers detector (ISL) was proposed as a part of the upgraded CDF detector at the RUN-II of the Tevatron mean value of pp collider at Fermilab, scheduled to start in year 2000. The ISL is a large-radius (20-30 cm) silicon tracker with a total active area of about 3.5 m. Located in the region between the silicon vertex detector and the central outer tracker, the ISL will allow tracking in the forward region and significantly improve it in the central area. Together with the SVX II the ISL forms a standalone, 3D silicon tracker. The challenge is to build a low-cost device which provides precise 3 D tracking in a approximately equal to 2 m long area with a minimal amount of material for the supporting structure. The conceptual design and the status of the project are reviewed.

Energy Technology Data Exchange (ETDEWEB)

This report discusses the experimental setup of experiment 814 at Brookhaven AGS. This experiment involves the collision of silicon ions with target nuclei. The detector systems are discussed primarily. (LSP)

Science.gov (United States)

Jan 18, 2011 ... The Radiation Assessment Detector, shown prior to its September 2010 ... This 360-degree panorama shows the vista from the location where ...