WorldWideScience

Sample records for residual atmosphere neutrons

  1. Atmospheric neutrons

    International Nuclear Information System (INIS)

    Preszler, A.M.; Moon, S.; White, R.S.

    1976-01-01

    Additional calibrations of the University of California double-scatter neutron and additional analysis corrections lead to the slightly changed neutron fluxes reported here. The theoretical angular distributions of Merker (1975) are in general agreement with our experimental fluxes but do not give the peaks for vertical upward and downward moving neutrons. The theoretical neutron escape current J 2 /sub pi/ (Merker, 1972; Armstrong et al., 1973) is in agreement with the experimental values from 10 to 100 MeV. Our experimental fluxes agree with those of the Kanbach et al. (1974) in the overlap region from 70 to 100 MeV

  2. CARBON NEUTRON STAR ATMOSPHERES

    International Nuclear Information System (INIS)

    Suleimanov, V. F.; Klochkov, D.; Werner, K.; Pavlov, G. G.

    2014-01-01

    The accuracy of measuring the basic parameters of neutron stars is limited in particular by uncertainties in the chemical composition of their atmospheres. For example, the atmospheres of thermally emitting neutron stars in supernova remnants might have exotic chemical compositions, and for one of them, the neutron star in Cas A, a pure carbon atmosphere has recently been suggested by Ho and Heinke. To test this composition for other similar sources, a publicly available detailed grid of the carbon model atmosphere spectra is needed. We have computed this grid using the standard local thermodynamic equilibrium approximation and assuming that the magnetic field does not exceed 10 8  G. The opacities and pressure ionization effects are calculated using the Opacity Project approach. We describe the properties of our models and investigate the impact of the adopted assumptions and approximations on the emergent spectra

  3. Neutron residual stress measurements in linepipe

    International Nuclear Information System (INIS)

    Law, Michael; Gnaepel-Herold, Thomas; Luzin, Vladimir; Bowie, Graham

    2006-01-01

    Residual stresses in gas pipelines are generated by manufacturing and construction processes and may affect the subsequent pipe integrity. In the present work, the residual stresses in eight samples of linepipe were measured by neutron diffraction. Residual stresses changed with some coating processes. This has special implications in understanding and mitigating stress corrosion cracking, a major safety and economic problem in some gas pipelines

  4. Single event phenomena in atmospheric neutron environments

    International Nuclear Information System (INIS)

    Gossett, C.A.; Hughlock, B.W.; Katoozi, M.; LaRue, G.S.; Wender, S.A.

    1993-01-01

    As integrated circuit technology achieves higher density through smaller feature sizes and as the airplane manufacturing industry integrates more sophisticated electronic components into the design of new aircraft, it has become increasingly important to evaluate the contribution of single event effects, primarily Single Event Upset (SEU), to the safety and reliability of commercial aircraft. In contrast to the effects of radiation on electronic systems in space applications for which protons and heavy ions are of major concern, in commercial aircraft applications the interactions of high energy neutrons are the dominant cause of single event effects. These high energy neutrons are produced by the interaction of solar and galactic cosmic rays, principally protons and heavy ions, in the upper atmosphere. This paper will describe direct experimental measurements of neutron-induced Single Event Effect (SEE) rates in commercial high density static random access memories in a neutron environment characteristic of that at commercial airplane altitudes. The first experimental measurements testing current models for neutron-silicon burst generation rates will be presented, as well as measurements of charge collection in silicon test structures as a function of neutron energy. These are the first laboratory SEE and charge collection measurements using a particle beam having a continuum energy spectrum and with a shape nearly identical to that observed during flight

  5. Neutron activation analysis of atmospheric aerosol

    International Nuclear Information System (INIS)

    Obrusnik, I.

    1986-01-01

    Neutron activation analysis (NAA) is a modern analytical method well suited for the analysis of atmospheric aerosols. Particular steps of the NAA procedure and especially different types of aerosol sampling and sample preparation for analysis are discussed in detail. Several possible NAA techniques are described and the advantages of a purely instrumental technique with short and long irradiation are pointed out. Important performance characteristics of the NAA method such as precision, accuracy, sensitivity and detection limits are also discussed. Different applications of NAA in environmental studies are reviewed. (author)

  6. Neutron diffraction measurements of residual stresses in NPP construction materials

    International Nuclear Information System (INIS)

    Hinca, R.; Bokuchava, G.

    2001-01-01

    Neutron diffraction is one of the most powerful methods for condensed matter studies. This method is used for non-destructive determination of residual stresses in material. The fundamental aspects of neutron diffraction are discussed, together with a brief description of the experimental facility. The principal advantage of using neutrons rather than the more conventional X-rays is the fact that neutron can penetrate deeply (2-4 cm for steel and more than 10 cm for aluminium) into metals to determine internal parameters within the bulk of materials. We present results of measurements residual stresses in NPP construction material - austenitic stainless steel (Cr-18%, Ni-10%, Ti-1%) coated with high-nickel alloy. (authors)

  7. Neutron measurement of residual stresses in a used railway rail

    International Nuclear Information System (INIS)

    Webster, P.J.; Low, K.S.; Mills, G.; Webster, G.A.

    1990-01-01

    The high resolution neutron diffraction technique has been applied to determine, non-destructively, the residual stress distribution developed in the head of a railway rail after normal service. Measurements were made, using the neutron strain scanner at the Institute Laue Langevin, Grenoble, on a transverse slice of rail 12mm thick taken from a section of straight track. The rail head was scanned in the three principal orientations in a series of parallel traverses sufficiently close to enable a two-dimensional matrix of data to be accumulated and vertical, transverse and longitudinal residual stress contours to be drawn. The results demonstrate the effectiveness and unique characteristics of the neutron technique to determine nondestructively and continuously the residual stresses inside engineering components

  8. Neutron activation analysis for noble metals in matte leach residues

    International Nuclear Information System (INIS)

    Hart, R.J.

    1978-01-01

    The development of the neutron activation analysis technique as a method for rapid and precise determinations of platinum group metals in matte leach residues depends on obtaining a method for effecting complete and homogeneous sample dilution. A simple method for solid dilution of metal samples is outlined in this study, which provided a basis for the accurate determination of all the noble metals by the Neutron Activation Analysis technique

  9. Steel research using neutron beam techniques. In-situ neutron diffraction, small-angle neutron scattering and residual stress analysis

    International Nuclear Information System (INIS)

    Sueyoshi, Hitoshi; Ishikawa, Nobuyuki; Yamada, Katsumi; Sato, Kaoru; Nakagaito, Tatsuya; Matsuda, Hiroshi; Arakaki, Yu; Tomota, Yo

    2014-01-01

    Recently, the neutron beam techniques have been applied for steel researches and industrial applications. In particular, the neutron diffraction is a powerful non-destructive method that can analyze phase transformation and residual stress inside the steel. The small-angle neutron scattering is also an effective method for the quantitative evaluation of microstructures inside the steel. In this study, in-situ neutron diffraction measurements during tensile test and heat treatment were conducted in order to investigate the deformation and transformation behaviors of TRIP steels. The small-angle neutron scattering measurements of TRIP steels were also conducted. Then, the neutron diffraction analysis was conducted on the high strength steel weld joint in order to investigate the effect of the residual stress distribution on the weld cracking. (author)

  10. Residual stress measurements by means of neutron diffraction

    International Nuclear Information System (INIS)

    Pintschovius, L.; Jung, V.; Macherauch, E.; Voehringer, O.

    1983-01-01

    A new method for the analysis of multiaxial residual stress states is presented, which is based on high resolution neutron diffraction. It is analogous to X-ray stress analysis, but the use of neutrons instead of X-rays allows the analysis of the stress distributions also in the interior of technical components in a non-destructive way. To prove the feasibility of the method, investigations of the loading stress distributions of an aluminium bar subjected to purely elastic bending were performed. Limiting factors due to the volume of the internal probe region and the sample thickness are discussed. Complete neutron residual stress analyses were carried out for a plastically deformed bending bar and a transformation-free water-quenched steel cylinder. The results are in fairly good agreement with theoretical expectations and with X-ray control measurements at the surface of the objects. (Auth.)

  11. Residual stress measurement in socket welded joints by neutron diffraction

    International Nuclear Information System (INIS)

    Hayashi, Makoto; Ishiwata, Masayuki; Minakawa, Noriaki; Funahashi, Satoru.

    1995-01-01

    Neutron diffraction measurements of lattice spacings provide the spatial map of residual stress near welds in ferritic steel socket joints. The high tensile stress greater than 200 MPa was found in the fusion and heat-affected zones in the hoop direction. However, the highest tensile stress in the axial direction at the weld root was about 110 MPa relatively lower than the expected value from the fatigue test results. The balancing compressive stress was found near the surface of the socket weld fusion zone. Heat treatment at 625degC for 2 hours was sufficient for the relief of residual stress in socket welds. (author)

  12. A primary simulation for residual stress neutron diffractometer

    International Nuclear Information System (INIS)

    Wang Shuying; Liu Lijuan; Sun Liangwei

    2012-01-01

    At present, neutron diffraction method is the unique and nondestructive method that can directly measure the residual stress distribution in deep materials and engineering components. It has an important application in engineering. A simulation of the flux at the position of the sample table was reported, and the resolution of the residual stress instrument was computed at the same time. The effect of the parameters of the second collimator on the flux at the sample position and the resolution of the instrument have been analyzed. The result indicated that the second collimator empress much on the neutron flux and the instrument resolution is well when the sample's diffraction angle is less than 120°. (authors)

  13. Residual stress measurement using the pulsed neutron source at LANSCE

    International Nuclear Information System (INIS)

    Bourke, M.A.M.; Goldstone, J.A.; Holden, T.M.

    1991-01-01

    The presence of residual stress in engineering components can effect their mechanical properties and structural integrity. Neutron diffraction is the only measuring technique which can make spatially resolved non-destructive strain measurements in the interior of components. By recording the change in the crystalline interplanar spacing, elastic strains can be measured for individual lattice reflections. Using a pulsed neutron source, all the lattice reflections are recorded in each measurement which allows anisotropic effects to be studied. Measurements made at the Manuel Lujan Jr Neutron Scattering Centre (LANSCE) demonstrate the potential for stress measurements on a pulsed source and indicate the advantages and disadvantages over measurements made on a reactor. 15 refs., 7 figs

  14. MODEL ATMOSPHERES FOR X-RAY BURSTING NEUTRON STARS

    International Nuclear Information System (INIS)

    Medin, Zach; Fontes, Christopher J.; Fryer, Chris L.; Hungerford, Aimee L.; Steinkirch, Marina von; Calder, Alan C.

    2016-01-01

    The hydrogen and helium accreted by X-ray bursting neutron stars is periodically consumed in runaway thermonuclear reactions that cause the entire surface to glow brightly in X-rays for a few seconds. With models of the emission, the mass and radius of the neutron star can be inferred from the observations. By simultaneously probing neutron star masses and radii, X-ray bursts (XRBs) are one of the strongest diagnostics of the nature of matter at extremely high densities. Accurate determinations of these parameters are difficult, however, due to the highly non-ideal nature of the atmospheres where XRBs occur. Observations from X-ray telescopes such as RXTE and NuStar can potentially place strong constraints on nuclear matter once uncertainties in atmosphere models have been reduced. Here we discuss current progress on modeling atmospheres of X-ray bursting neutron stars and some of the challenges still to be overcome.

  15. MODEL ATMOSPHERES FOR X-RAY BURSTING NEUTRON STARS

    Energy Technology Data Exchange (ETDEWEB)

    Medin, Zach; Fontes, Christopher J.; Fryer, Chris L.; Hungerford, Aimee L. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Steinkirch, Marina von; Calder, Alan C. [Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794 (United States)

    2016-12-01

    The hydrogen and helium accreted by X-ray bursting neutron stars is periodically consumed in runaway thermonuclear reactions that cause the entire surface to glow brightly in X-rays for a few seconds. With models of the emission, the mass and radius of the neutron star can be inferred from the observations. By simultaneously probing neutron star masses and radii, X-ray bursts (XRBs) are one of the strongest diagnostics of the nature of matter at extremely high densities. Accurate determinations of these parameters are difficult, however, due to the highly non-ideal nature of the atmospheres where XRBs occur. Observations from X-ray telescopes such as RXTE and NuStar can potentially place strong constraints on nuclear matter once uncertainties in atmosphere models have been reduced. Here we discuss current progress on modeling atmospheres of X-ray bursting neutron stars and some of the challenges still to be overcome.

  16. Residual Stress Analysis of Aircraft Part using Neutron Beam

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Eun Joo; Seong, Baek Seok; Sim, Cheul Muu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2012-05-15

    A precise measurement of the residual stress magnitude and distribution is an important factor to evaluate the lifetime or safety of the materials, because the residual stress affects the material properties, such as the strength, fatigue, etc. In the case of a fighter jet, the lifetime and safety of the parts of the landing gear are more important than that of a passenger airplane because of its frequent take offs and landings. In particular in the case of training a fighter jet, a precise evaluation of life time for the parts of the landing gear is strongly required for economic reason. In this study, the residual stress of a part of the landing gear of the training fighter jet which is used to fix the landing gear to the aircraft body was investigated. The part was used for 2000 hours of flight, which corresponds to 10 years. During this period, the fighter jet normally takes off and lands more than 2000 times. These frequent take off and landing can generate residual stress and cause a crack in the part. By measuring the neutron diffraction peaks, we evaluated the residual stress of the landing gear part

  17. Analysis of atmospheric particulate samples via instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Greenberg, R.R.

    1990-01-01

    Instrumental neutron activation analysis (INAA) is a powerful analytical technique for the elemental characterization of atmospheric particulate samples. It is a true multielement technique with adequate sensitivity to determine 30 to 40 elements in a sample of atmospheric particulate material. Its nondestructive nature allows sample reanalysis by the same or a different analytical technique. In this paper as an example of the applicability of INAA to the study of atmospheric particulate material, a study of the emissions from municipal incinerators is described

  18. Principles of the measurement of residual stress by neutron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Webster, G A; Ezeilo, A N [Imperial Coll. of Science and Technology, London (United Kingdom). Dept. of Mechanical Engineering

    1996-11-01

    The presence of residual stresses in engineering components can significantly affect their load carrying capacity and resistance to fracture. In order to quantify their effect it is necessary to know their magnitude and distribution. Neutron diffraction is the most suitable method of obtaining these stresses non-destructively in the interior of components. In this paper the principles of the technique are described. A monochromatic beam of neutrons, or time of flight measurements, can be employed. In each case, components of strain are determined directly from changes in the lattice spacings between crystals. Residual stresses can then be calculated from these strains. The experimental procedures for making the measurements are described and precautions for achieving reliable results discussed. These include choice of crystal planes on which to make measurements, extent of masking needed to identify a suitable sampling volume, type of detector and alignment procedure. Methods of achieving a stress free reference are also considered. A selection of practical examples is included to demonstrate the success of the technique. (author) 14 figs., 1 tab., 18 refs.

  19. Principles of the measurement of residual stress by neutron diffraction

    International Nuclear Information System (INIS)

    Webster, G.A.; Ezeilo, A.N.

    1996-01-01

    The presence of residual stresses in engineering components can significantly affect their load carrying capacity and resistance to fracture. In order to quantify their effect it is necessary to know their magnitude and distribution. Neutron diffraction is the most suitable method of obtaining these stresses non-destructively in the interior of components. In this paper the principles of the technique are described. A monochromatic beam of neutrons, or time of flight measurements, can be employed. In each case, components of strain are determined directly from changes in the lattice spacings between crystals. Residual stresses can then be calculated from these strains. The experimental procedures for making the measurements are described and precautions for achieving reliable results discussed. These include choice of crystal planes on which to make measurements, extent of masking needed to identify a suitable sampling volume, type of detector and alignment procedure. Methods of achieving a stress free reference are also considered. A selection of practical examples is included to demonstrate the success of the technique. (author) 14 figs., 1 tab., 18 refs

  20. Hydrocracking of atmospheric distillable residue of Mongolian oil

    Directory of Open Access Journals (Sweden)

    Ts Tugsuu

    2014-09-01

    Full Text Available Many catalytic processes to refine heavy part of crude oil have attracted much interest due to declining reserves of light crude oils. This study focused on hydrocracking process of atmospheric distillable residue of Mongolian crude oil in the first time compared to those of other countries. Residue samples were hydrocracked with a commercial catalyst at 450°C, 460°C, 470°C for 2 h under hydrogen pressure of 10 MPa. The amount of residual fraction (350°Catmospheric distillable residue from Tamsagbulag crude oil. When the ME-AR was hydrocracked, the high consumption of hydrogen was related to the lowest H/C atomic ratio of feed atmospheric residue. The amount of liquid fractions (BP<350°C including gaseous products increased from 45.4wt% to 89.2wt%, when the reaction temperature increased from 450°C to 470°C. The highest yield of the middle fraction for each sample was observed at temperature of 460°C. On the other hand, the effect of temperature on the yield of middle fraction was not so high as compared with the yields of other fractions. The contents of n-paraffins on midlle and heavy fractions of TB-AR, DQ-AR were similar, but ME-AR’s was around 2 times lower than other after hydrocracking runs.DOI: http://dx.doi.org/10.5564/mjc.v12i0.166 Mongolian Journal of Chemistry Vol.12 2011: 24-28 

  1. Residual stress evaluation by neutron and synchrotron radiation

    International Nuclear Information System (INIS)

    Lodini, A.

    2000-01-01

    This lecture is dedicated to the residual stress evaluation using neutron and X ray synchrotron radiation. Residual stress evaluation is an important step for the improvement or the performance of materials, the control of the deformation of the components and the understanding of industrial process. In general, residual stress has various origins: mechanical, thermal, thermomechanical or thermochemical. In general, these residual stresses are caused by plastic deformation, or some source of local incompatibilities and are generated by three fundamental physical origins: plastic flow, volume change and thermal dilatation. These incompatibilities are compensated for partly by the elastic deformation that generates some internal stresses. In the solid, these local incompatibilities are caused by crystal defects. The exact origin of a stress is going to depend on the scale of observation. A classification of the residual stresses in three orders, related to the scale on which one considers materials, is proposed. The diffraction method for determination of macrostresses is based on the measurement of interplanar spacing for various direction in a diffraction experiment. Different examples are proposed. Polycrystalline grains or composite have different physical and elastic properties hence the stress for a particular grains or phase differs from the average value (value of macrostress). This difference is defined as the second order stress. The second order stresses occur because of small scale anisotropy or inhomogeneity in the material : for example, due to mismatch in coefficient of thermal expansion, elastic constants or plastic flow. However, the second order stress averaged over all grains or phase is not equal to zero and this average is called the mismatch stress. Using the experimental macro stress it is possible to calculate the mismatch stresses. More recently, this technique of diffraction has also been applied for the determination of microstrain (third

  2. Neutron activation analysis of atmospheric aerosols

    International Nuclear Information System (INIS)

    Riekstinya, D.V.; Mednis, I.V.; Veveris, O.Eh.

    1987-01-01

    A review of studies by Soviet and foreign authors on radioactivation analysis is presented. Instrumental neutron activation analysis (INAA) techniques have been developed providing the possibility to determine a number of elements in very small portions of aerosols for pollutanless areas of the Earth. Two ways of INAA are presented: with long- and short-living radionuclides. The Antarctic and the Indian Ocean aerosol samples have been analysed for 26 microelements. It has been stated that restrictions of the detection limits attained relate to high proportions of certain elements and their nonhomogeneous distribution in filters. The detection limits can be lowered by the filtered air volume growth per unit of the filter area

  3. Mapping residual and internal stress in materials by neutron diffraction

    International Nuclear Information System (INIS)

    Withers, Ph.J.

    2007-01-01

    Neutron diffraction provides one of the few means of mapping residual stresses deep within the bulk of materials and components. This article reviews the basic scientific methodology by which internal strains and stresses are inferred from recorded diffraction peaks. Both conventional angular scans and time-of-flight measurements are reviewed and compared. Their complementarity with analogous synchrotron X-ray methods is also highlighted. For measurements to be exploited in structural integrity calculations underpinning the safe operation of engineering components, measurement standards have been defined and the major findings are summarised. Examples are used to highlight the unique capabilities of the method showing how it can provide insights ranging from the basic physics of slip mechanisms in hexagonal polycrystalline materials, through the materials optimisation of stress induced transformations in smart nano-materials, to the industrial introduction of novel friction welding processes exploiting stress residual measurements transferred from prototype sub-scale tests to the joining of full-scale aero-engine assemblies. (author)

  4. Residual stress characterization of steel TIG welds by neutron diffraction and by residual magnetic stray field mappings

    Science.gov (United States)

    Stegemann, Robert; Cabeza, Sandra; Lyamkin, Viktor; Bruno, Giovanni; Pittner, Andreas; Wimpory, Robert; Boin, Mirko; Kreutzbruck, Marc

    2017-03-01

    The residual stress distribution of tungsten inert gas welded S235JRC+C plates was determined by means of neutron diffraction (ND). Large longitudinal residual stresses with maxima around 600 MPa were found. With these results as reference, the evaluation of residual stress with high spatial resolution GMR (giant magneto resistance) sensors was discussed. The experiments performed indicate a correlation between changes in residual stresses (ND) and the normal component of local residual magnetic stray fields (GMR). Spatial variations in the magnetic field strength perpendicular to the welds are in the order of the magnetic field of the earth.

  5. Residual stress characterization of steel TIG welds by neutron diffraction and by residual magnetic stray field mappings

    Energy Technology Data Exchange (ETDEWEB)

    Stegemann, Robert, E-mail: Robert.Stegemann@bam.de [Bundesanstalt für Materialforschung und -prüfung (BAM), Unter den Eichen 87, 12200 Berlin (Germany); Cabeza, Sandra; Lyamkin, Viktor; Bruno, Giovanni; Pittner, Andreas [Bundesanstalt für Materialforschung und -prüfung (BAM), Unter den Eichen 87, 12200 Berlin (Germany); Wimpory, Robert; Boin, Mirko [HZB Helmholtz-Zentrum Berlin, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Kreutzbruck, Marc [Bundesanstalt für Materialforschung und -prüfung (BAM), Unter den Eichen 87, 12200 Berlin (Germany); IKT, University of Stuttgart, Pfaffenwaldring 32, 70569 Stuttgart (Germany)

    2017-03-15

    The residual stress distribution of tungsten inert gas welded S235JRC+C plates was determined by means of neutron diffraction (ND). Large longitudinal residual stresses with maxima around 600 MPa were found. With these results as reference, the evaluation of residual stress with high spatial resolution GMR (giant magneto resistance) sensors was discussed. The experiments performed indicate a correlation between changes in residual stresses (ND) and the normal component of local residual magnetic stray fields (GMR). Spatial variations in the magnetic field strength perpendicular to the welds are in the order of the magnetic field of the earth. - Highlights: • Comparison of magnetic microstructure with neutron diffraction stress analysis. • High spatial resolution magnetic stray field images of hypereutectoid TIG welds. • Spatial variations of the stray fields are below the magnetic field of the earth. • GMR spin valve gradiometer arrays adapted for the evaluation of magnetic microstructures. • Magnetic stray fields are closely linked to microstructure of the material.

  6. Neutron diffraction measurements of residual stress in a powder metallurgy component

    International Nuclear Information System (INIS)

    Schneider, L.C.R.; Hainsworth, S.V.; Cocks, A.C.F.; Fitzpatrick, M.E.

    2005-01-01

    Residual stresses in a typical industrial green component were determined using neutron diffraction. The measured residual stresses were found to correlate with cross-sectional variations. Residual stress at the edge of the compact in contact with the die wall during compaction reached up to +80 MPa (tension) and -100 MPa (compression)

  7. Residual stress measurement of the jacket material for ITER coil by neutron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Tsuchiya, Yoshinori [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-03-01

    Nickel-Iron based super alloy INCOLOY 908 is used for the jacket of a central solenoid coil (CS coil) of the International Thermonuclear Experimental Reactor (ITER). INCOLOY 908, however, has a possibility of fracture due to Stress Accelerated Grain Boundary Oxidation (SAGBO) under a tensile residual stress beyond 200MPa. Therefore it is necessary to measure the residual stress of the jacket to avoid SAGBO. We performed residual stress measurement of the jacket by neutron diffraction using the neutron diffractometer for residual stress analysis (RESA) installed at JRR-3M in JAERI. A sample depth dependence of internal strain was obtained from the (111) plane spacing. A residual stress distribution was calculated from the strain using Young`s modulus and Poisson`s ratio that were evaluated by a tensile test with neutron diffraction. The result shows that the tensile residual stress exceeds 200MPa of the SAGBO condition in some regions inside the jacket. (author)

  8. Residual stress distribution in carbon steel pipe welded joint measured by neutron diffraction

    International Nuclear Information System (INIS)

    Hayashi, Makoto; Ishiwata, Masayuki; Morii, Yukio; Minakawa, Nobuaki

    2000-01-01

    In order to estimate crack growth behavior of fatigue and stress corrosion cracking in pipes, the residual stress distribution near the pipe weld region has to be measured through the wall thickness. Since the penetration depth of neutron is deep enough to pass through the thick pipe wall, the neutron diffraction technique for the residual stress measurement is effective for this purpose. At the first step the residual stress distribution near the weld region in a butt-welded carbon steel pipe was measured by the neutron diffraction. Significant stresses extended only to a distance of 30 mm from the center of the weld. The major tensile stresses occurred in the hoop direction in the fusion and heat affected zones of the weldment, and they attained a level greater than 200 MPa through the thickness. While the axial residual stress at the inside surface was 50 MPa, the stress at the outside surface was -100 MPa. The comparison of residual stress distributions measured by the neutron diffraction, the X-ray diffraction and the strain gauge method reveals that the neutron diffraction is the most effective for measuring the residual stress inside the structural components. (author)

  9. Evaluation of in-plant neutron coincidence counters for the measurement of molten salt extraction residues

    International Nuclear Information System (INIS)

    Langner, D.G.; Russo, P.A.; Wachter, J.R.

    1993-01-01

    Americium is extracted from plutonium by a molten salt extraction (MSE) process. The residual americium-laden salts are a significant waste stream in this pyrochemical purification process. Rapid assay of MSE residues is desirable to minimize the exposure of personnel to these often high-level emissions. However, the quantitative assay of plutonium in MSE residues is difficult. Variable, unknown (a,n) rates and variable emitted-neutron energy spectra preclude the use of standard neutron coincidence counting techniques with old-generation neutron coincidence counters. Gamma-ray assay methods have not been successful with some residues because of random lumps of plutonium metal. In this paper, we present measurements of MSE residues with two state-of-the-art neutron coincidence counters at the Los Alamos Plutonium Processing Facility: an in-line counter built for the assay of bulk waste material and the pyrochemical multiplicity counter that underwent test and evaluation at that facility. Both of these counters were designed to minimize the effects on measurements of variations in the sample geometry and variable energy spectra of emitted neutrons. These results are compared to measurements made with an HLNCII and with a 20-yr-old in-line well counter. The latter two counters are not optimized in ft sense. We conclude that the newer counters provide significantly improved assay results. The pyrochemical multiplicity counter operated in the conventional coincidence mode provided the best assays overall

  10. A study on the neoasozine residues in rice grain by neutron activation method

    International Nuclear Information System (INIS)

    Kim, Y.H.; Lee, K.J.; Lee, S.R.

    1981-01-01

    Residues of neoasozine in rice grain were determined by neutron activation and colorimetric techniques. Twice application of the chemical before flowering did not lead to any increased residue level while 4-times application resulted in significant increase in the residue level up to 0.54 - 0.75 mg As 2 O 3 /kg. The partition ratio of arsenic residues into polished rice grain and bran was 73 : 27 in 100 % polishing while most of the residues in the bran was transferred to oil cake fraction during solvent extraction, reaching up to 2.9 mg As 2 O 3 /kg. The neutron activation technique was advantageous because of its high sensitivity and the smaller sample amounts required for analysis. (author)

  11. Neutron diffraction measurement of residual stress in NPP construction materials

    International Nuclear Information System (INIS)

    Hinca, R.; Bokuchava, G.

    2000-01-01

    The aim of the investigation is to study the level of residual stresses induced by the surfacing in the weld deposit zone and in the base metal, where considerable thermal gradients are present. Surfacing high-nickel filler on an austenitic base metal is one of techniques in repair of primary collector the primary circuit of nuclear power plant type VVER. The repair technology was developed at Welding Research Institute Bratislava. Measurements of residual stresses in the weld overlay and the base metal are necessary for approving the mechanical analysis and verifying of residual stresses determination on welded material by numerical weld g computer simulation. Investigations of residual stresses are important for developing optimal welding techniques. (authors)

  12. Through-thickness Residual Stress Measurement by Neutron Diffraction in Cu+W Plasma Spray Coatings

    Czech Academy of Sciences Publication Activity Database

    Luzin, V.; Matějíček, Jiří; Gnäupel-Herold, T.

    2010-01-01

    Roč. 652, č. 652 (2010), s. 50-56 ISSN 1662-9752. [International Conference on Mechanical Stress Evaluation by Neutrons and Synchrotron Radiation/5th./. Mito, 10.11.2009-12.11.2009] R&D Projects: GA MŠk ME 901 Institutional research plan: CEZ:AV0Z20430508 Keywords : fusion materials * plasma sprayed coatings * residual stress * neutron diffraction Subject RIV: JG - Metallurgy http://www.scientific.net/MSF.652.50

  13. Time dependent worldwide distribution of atmospheric neutrons and of their products. I, II, III.

    Science.gov (United States)

    Merker, M.; Light, E. S.; Verschell, H. J.; Mendell, R. B.; Korff, S. A.

    1973-01-01

    Review of the experimental results obtained in a series of measurements of the fast neutron cosmic ray spectrum by means of high-altitude balloons and aircraft. These results serve as a basis for checking a Monte Carlo calculation of the entire neutron distribution and its products. A calculation of neutron production and transport in the earth's atmosphere is then discussed for the purpose of providing a detailed description of the morphology of secondary neutron components. Finally, an analysis of neutron observations during solar particle events is presented. The Monte Carlo output is used to estimate the contribution of flare particles to fluctuations in the steady state neutron distributions.

  14. Residual stress determination in thermally sprayed metallic deposits by neutron diffraction

    International Nuclear Information System (INIS)

    Keller, Thomas; Margadant, Nikolaus; Pirling, Thilo; Riegert-Escribano, Maria J.; Wagner, Werner

    2004-01-01

    Neutron diffraction was used to obtain spatially resolved strain and stress profiles in thermally sprayed metallic 'NiCrAlY' deposits (chemical composition 67 wt.% Ni, 22 wt.% Cr, 10 wt.% Al, 1 wt.% Y) and the underlying steel substrates. Samples of four different spray techniques were analyzed: atmospheric and water stabilized plasma spraying (APS and WSP), flame spraying (FS) and wire arc spraying (WAS). The results are quantitatively compared with the average in-plane residual stress determined by complementary bending tests and the hole drilling technique. While the stress profiles from the surface to the interface in the deposits are similar for all investigated spray techniques, their absolute values and gradients vary strongly. This is attributed to different quenching stresses from the impinging particles, different thermal histories the deposit/substrate systems undergo during the spraying and subsequent cooling, and also to different coating properties. In the water stabilized plasma sprayed and the wire arc sprayed deposits, a gradient in the stress-free lattice parameter was observed. Crack formation is found to be a dominant mechanism for stress relaxation in the surface plane

  15. Residual stress determination in thermally sprayed metallic deposits by neutron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Keller, Thomas; Margadant, Nikolaus; Pirling, Thilo; Riegert-Escribano, Maria J.; Wagner, Werner

    2004-05-25

    Neutron diffraction was used to obtain spatially resolved strain and stress profiles in thermally sprayed metallic 'NiCrAlY' deposits (chemical composition 67 wt.% Ni, 22 wt.% Cr, 10 wt.% Al, 1 wt.% Y) and the underlying steel substrates. Samples of four different spray techniques were analyzed: atmospheric and water stabilized plasma spraying (APS and WSP), flame spraying (FS) and wire arc spraying (WAS). The results are quantitatively compared with the average in-plane residual stress determined by complementary bending tests and the hole drilling technique. While the stress profiles from the surface to the interface in the deposits are similar for all investigated spray techniques, their absolute values and gradients vary strongly. This is attributed to different quenching stresses from the impinging particles, different thermal histories the deposit/substrate systems undergo during the spraying and subsequent cooling, and also to different coating properties. In the water stabilized plasma sprayed and the wire arc sprayed deposits, a gradient in the stress-free lattice parameter was observed. Crack formation is found to be a dominant mechanism for stress relaxation in the surface plane.

  16. Residual Stress Analysis for Engineering Applications by Means of Neutron Diffraction

    International Nuclear Information System (INIS)

    Gndupel-Herold, Thomas; Brand, Paul C.; Prask, Henry J.

    1999-01-01

    The economic and scientific importance of neutron diffraction residual stress analysis has led to an increasing number of suitable instruments worldwide. Recently, a dedicated state-of-the-art diffractometer has been installed at the National Institute of Standards and Technology reactor. It has been used for a variety of measurements on basic and engineering stress problems. Among the most prominent examples that have been investigated are residual stresses in rails, weldments, and plasma-sprayed coatings

  17. Comparison of neutron and synchrotron diffraction measurements of residual stress in bead-on-plate weldments

    International Nuclear Information System (INIS)

    Paradowska, A.M.; Price, J.W.; Finlayson, T.R.; Lienert, U.; Ibrahim, R.

    2010-01-01

    This paper explores the use of neutron and synchrotron diffractions for the evaluation of residual stresses in welded components. It has been shown that it is possible to achieve very good agreement between the two independent diffraction techniques. This study shows the significance of the weld start and end sites on the residual strain/stress distribution. Quantitative evaluation of the residual stress development process for multibead weldments has been presented. Some measurements were also taken before and after postweld stress relieving to establish the reduction and redistribution of the residual stress. The detailed measurements of residual stress around the weld achieved in this work significantly improve the knowledge and understanding of residual stress in welded components.

  18. Measurement of residual stress in materials using neutrons. Proceedings of a technical meeting

    International Nuclear Information System (INIS)

    2005-06-01

    One of the objectives of the IAEA's project on effective utilization of research reactors is to promote the use of the existing research reactors based on their capabilities and is implemented through workshops and technical meetings. Measurement of residual stress is one of the techniques that find wide applications in materials development and testing. The Technical Meeting on Measurement of Residual Stress Using Neutrons was organized to meet this objective. This publication is the outcome of the deliberations during the meeting and the presentations by the participants and is addressed to the research reactor managers, users and designers of facilities for reactor utilization. It will especially benefit those seeking to develop new facilities or upgrade the existing ones to enhance the utilization of their research reactors. Experts with a long experience in developing and using neutron beam instruments in high flux and medium flux research reactors participated in this technical meeting. They presented the design, development and utilization of the facilities at their respective centres and reviewed the current status of the residual stress measurements using neutron beams from research reactors. The sessions included brainstorming on the methodology and data analysis, characterization and standardization of the equipment and identifying the scope for further development. This publication refers to the determination of residual and/or applied stresses in polycrystalline materials using neutron diffraction technique. Stress is developed during the synthesis and use of materials such as alloys and compounds. Measurement of residual stress is essential to improve the quality of synthesized materials and diagnosis of failure and/or reliability of fabricated components. Neutron scattering has played an important role in studying structure and dynamics of condensed matter. Neutron scattering is a non-destructive technique and is useful for testing large samples. The

  19. Single Event Upset in Static Random Access Memories in Atmospheric Neutron Environments

    Science.gov (United States)

    Arita, Yutaka; Takai, Mikio; Ogawa, Izumi; Kishimoto, Tadafumi

    2003-07-01

    Single-event upsets (SEUs) in a 0.4 μm 4 Mbit complementary metal oxide semiconductor (CMOS) static random access memory (SRAM) were investigated in various atmospheric neutron environments at sea level, at an altitude of 2612 m mountain, at an altitude of commercial airplane, and at an underground depth of 476 m. Neutron-induced SEUs increase with the increase in altitude. For a device with a borophosphosilicate glass (BPSG) film, SEU rates induced by thermal neutrons increase with the decrease in the cell charge of a memory cell. A thermal neutron-induced SEU is significant in SRAMs with a small cell charge. With the conditions of small cell charge, thermal neutron-induced SEUs account for 60% or more of the total neutron-induced SEUs. The SEU rate induced by atmospheric thermal neutrons can be estimated by an acceleration test using 252Cf.

  20. Single event upset in static random access memories in atmospheric neutron environments

    CERN Document Server

    Arita, Y; Ogawa, I; Kishimoto, T

    2003-01-01

    Single-event upsets (SEUs) in a 0.4 mu m 4Mbit complementary metal oxide semiconductor (CMOS) static random access memory (SRAM) were investigated in various atmospheric neutron environments at sea level, at an altitude of 2612 m mountain, at an altitude of commercial airplane, and at an underground depth of 476m. Neutron-induced SEUs increase with the increase in altitude. For a device with a borophosphosilicate glass (BPSG) film, SEU rates induced by thermal neutrons increase with the decrease in the cell charge of a memory cell. A thermal neutron-induced SEU is significant in SRAMs with a small cell charge. With the conditions of small cell charge, thermal neutron-induced SEUs account for 60% or more of the total neutron-induced SEUs. The SEU rate induced by atmospheric thermal neutrons can be estimated by an acceleration test using sup 2 sup 5 sup 2 Cf. (author)

  1. Residual stresses in cold-coiled helical compression springs for automotive suspensions measured by neutron diffraction

    Czech Academy of Sciences Publication Activity Database

    Matějíček, Jiří; Brand, P. C.; Drews, A. R.; Krause, A.; Lowe-Ma, C.

    2004-01-01

    Roč. 367, 1-2 (2004), s. 306-311 ISSN 0921-5093 Institutional research plan: CEZ:AV0Z2043910 Keywords : residual stress, automotive springs, neutron diffraction Subject RIV: JB - Sensors, Measurment, Regulation Impact factor: 1.445, year: 2004

  2. Residual stresses determination by neutron diffraction in a 100Cr6 chromium steel bearing ring

    Czech Academy of Sciences Publication Activity Database

    Rogante, M.; Martinat, G.; Mikula, Pavol; Vrána, Miroslav

    2013-01-01

    Roč. 51, č. 5 (2013), s. 275-281 ISSN 0023-432X R&D Projects: GA MŠk(XE) LM2011019 Institutional support: RVO:61389005 Keywords : 100Cr6 steel * rings * martensitic hardening * tempering * residual stress es * neutron diffraction Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.546, year: 2013

  3. Residual stress in sprayed Ni+5%Al coatings determined by neutron diffraction

    CERN Document Server

    Matejicek, J; Gnaeupel-Herold, T; Prask, H J

    2002-01-01

    Coatings of nickel-based alloys are used in numerous high-performance applications. Their properties and lifetimes are influenced by factors such as residual stress. Neutron diffraction is a powerful tool for nondestructive residual stress determination. In this study, through-thickness residual stress profiles in Ni+5%Al coatings on steel substrates were determined. Two examples of significantly different spraying techniques - plasma spraying and cold spraying - are highlighted. Different stress-generation mechanisms are discussed with respect to process parameters and material properties. (orig.)

  4. Measurement of residual stress in textured Al alloy by neutron diffraction method

    International Nuclear Information System (INIS)

    Okido, S.; Hayashi, M.; Tanaka, K.; Akiniwa, Y.; Minakawa, N.; Morii, Y.

    1999-01-01

    Residual stress generated in a shrunken aluminum alloy specimen, which was prepared for the round robin test conducted by VAMAS (Versailles Project on Advanced Materials and Standards) TWA-20 organized for the purpose of standardizing residual stress measurement methods, was evaluated by a neutron diffraction method. The main purpose of the round robin test was to assess the reproducibility of data obtained with the measurement facilities of the participants. The general standard of the Residual Stress Analyzer (RESA) constructed in the Japan Atomic Energy Research Institute was verified from the measured residual strains, which were equivalent to the values calculated by FEM and values measured by the research facilities in North America. Residual stress was calculated from residual strain in three perpendicular directions. The diffraction intensities were dependent on measurement directions since the prepared specimen possessed texture. Diffraction profiles in directions having a weak diffraction intensity caused an inaccurate evaluation of the residual stress. To solve this problem, a new method for evaluating residual stress with respect to diffraction plane dependency of the elastic constant was applied. The diffraction plane giving the highest intensity among 110, 200, and 220 diffraction was used to evaluate the residual strain in each of three directions. The residual strain obtained on the used diffraction plane was converted to the equivalent strain for the defined diffraction plane using the ratio of elastic constants of these two planes. The developed evaluation method achieved highly accurate measurement and remarkable efficiency in the measurement process. (author)

  5. Residual Stress Measurement of Coarse Crystal Grain in Aluminium Casting Alloy by Neutron Diffraction

    International Nuclear Information System (INIS)

    Nishida, Masayuki; Watanabe, Yoshitaka; Hanabusa, Takao

    2009-01-01

    Full text: Neutron stress measurement can detect strain and stress information in deep region because of large penetration ability of neutron beams. The present paper describes procedure and results in the residual stress measurement of aluminium casting alloy by neutron diffraction. Usually, the aluminium casting alloy includes the large crystal grains. The existence of large crystal grains makes it difficult to estimate the residual stresses in highly accuracy. In this study, the modified three axial method using Hook's equation was employed for neutron stress measurement. These stress measurements were performed under the two kinds of new techniques. One is a rocking curve method to calculate the principal strains in three directions. The peak profiles which appear discretely on rocking curves were translated to principle stresses by the Bragg law and the basic elastic theory. Another is the consideration of measurement positions and the edge effect in the neutron irradiated area (volume gage). The edge effect generates the errors of 2θ-peak position in the neutron stress measurement. In this study, the edge effect was investigated in detail by a small bit of copper single crystal. The copper bit was moved and scanned on three dimensionally within the gage volume. Furthermore, the average strains of symmetrical positions are measure by the sample turning at 180 degrees, because the error distributions of the 2θ-peak position followed to positions inside the gage volume. Form these results of this study, the residual stresses in aluminium casting alloy which includes the large crystal grains were possible to estimate by neutron stress measurement with the rocking curve method and the correction of the edge effect. (author)

  6. Experimental determination of residual stress by neutron diffraction in a boiling water reactor core shroud

    International Nuclear Information System (INIS)

    Payzant, A.; Spooner, S.; Zhu, Xiaojing; Hubbard, C.R.

    1996-01-01

    Residual strains in a 51 mm (2-inch) thick 304L stainless steel plate have been measured by neutron diffraction and interpreted in terms of residual stress. The plate, measuring (300 mm) in area, was removed from a 6m (20-ft.) diameter unirradiated boiling water reactor core shroud, and included a multiple-pass horizontal weld which joined two of the cylindrical shells which comprise the core shroud. Residual stress mapping was undertaken in the heat affected zone, concentrating on the outside half of the plate thickness. Variations in residual stresses with location appeared consistent with trends expected from finite element calculations, considering that a large fraction of the residual hoop stress was released upon removal of the plate from the core shroud cylinder

  7. The residual proton-neutron interaction and nuclear collectivity

    International Nuclear Information System (INIS)

    Casten, R.F.

    1990-01-01

    The essential role of the valence, residual p-n interaction in the development of collectivity, though long known in general terms, has recently become increasingly apparent. A brief review of the p-n interaction is given, including some very basic nuclear data that illustrate its effects and the phenomenological N p N n scheme and the P-factor. This is followed by a discussion of recent experimental extractions of p-n matrix elements throughout the periodic table and theoretical efforts to understand them, in terms of both Shell and Nilsson models. 20 refs., 13 figs

  8. Evaluation of the U-Pu residual mass from spent fuel assemblies with passive and active neutronic methods

    International Nuclear Information System (INIS)

    Bignan, G.; Martin-Deidier, L.

    1991-01-01

    The interpretation of passive and active neutronic measurements to evaluate the U-Pu residual mass in spent fuel assemblies is presented as follows: passive neutron measurements are well correlated to the plutonium mass, active neutron measurements give information linked to the fissile mass content of the assembly ( 235 U + 239 Pu + 241 Pu) and, using the passive neutron measurement, lead to the 235 U mass content of the assemblies

  9. Residual stresses determination in an 8 mm Incoloy 800H weld via neutron diffraction

    International Nuclear Information System (INIS)

    Chen, Xizhang; Zhang, Shu Yan; Wang, Jingjun; Kelleher, Joe F.

    2015-01-01

    Highlights: • Stress through thickness at 5 mm from weld centerline indicates a “U” distribution. • Declining of tensile stress through thickness occurred at weld centerline. • Residual stress between layers is the lowest. - Abstract: To investigate the distribution of residual stresses, the 8 mm 800H alloy was joined by multi-layer butt TIG process. Residual stresses in the longitudinal, transverse and normal directions were measured via neutron diffraction. These residual stress measurements were taken at a series of points 2 mm below the top surface, covering the fusion zone, heat affected zone (HAZ) and base metal. In addition, two lines of longitudinal residual stress values at the weld centerline and 5 mm from weld centerline through thickness were measured. Results show that both the longitudinal and transverse stresses from the weld centerline to base metal are mainly tensile stresses. The longitudinal residual stress is the largest, with a maximum value of 330 MPa. As for the normal residual stress, the weld zone shows tensile stress, while the HAZ shows compressive stress. The middle of the thickness shows compressive residual stress along the thickness direction. The longitudinal stress at weld centerline through thickness reveals the interlayer heat treat effects leads to a declining of tensile stress. While the stress at 5 mm from weld centerline indicates a “U” distribution due to the mixed microstructure close to fusion line. With the increasing distance from weld seam, the residual stress decreases gradually

  10. Extended Lipkin-type models with residual proton-neutron interaction

    International Nuclear Information System (INIS)

    Stoica, S.

    1999-01-01

    Extended Lipkin-Meshkov-Glick (LMG) models for testing the Random Phase Approximation (RPA) and proton-neutron Random Phase Approximation (pnRPA) methods are developed taking into account explicitly the proton and neutron degrees of freedom. First, an extended LMG model for testing RPA is developed. The proton and neutron Hamiltonians are taken to be of the LMG form and, in addition, a residual proton-neutron interaction is included. Exact solutions in a SU(2) x SU(2) basis as well as the RPA solutions for the energy spectrum of the model Hamiltonian are obtained. Then, the behaviour of the first collective excited state is studied as a function of the interaction parameters of the model using the exact and RPA methods. Secondly, an extended LMG model for testing pnRPA method is developed. Besides the proton and neutron single particle terms two types of residual proton-neutron interactions, one simulating a particle-particle and the other a particle-hole interaction, are included in the model Hamiltonian, so that the model is exactly solvable in an isospin SU(2) x SU(2) basis. The exact and pnRPA spectra of the model Hamiltonian are calculated as a function of the model parameters and compared to each other. Furthermore, charge-changing operators simulating a nuclear beta decay and their action on eigenfunctions of the model Hamiltonian are defined, and transition amplitude of them are calculated using exact and pnRPA wave functions. The best agreement between the exact RPA-type calculations for spectra and transitions, was obtained when the correlated RPA ground state, instead of the uncorrelated HF ground state was employed and when both kinds of residual interactions (i.e. like- and unlike-particle two-body interactions) are included in the model Hamiltonians. (author)

  11. Irradiation and modified atmosphere packaging effects on residual nitrite, ascorbic acid, nitrosomyoglobin, and color in sausage.

    Science.gov (United States)

    Ahn, Hyun-Joo; Jo, Cheorun; Lee, Ju-Woon; Kim, Jae-Hyun; Kim, Kee-Hyuk; Byun, Myung-Woo

    2003-02-26

    The present study was undertaken to evaluate the irradiation and modified atmosphere packaging effects on emulsion-type cooked pork sausage during storage for 4 weeks. CO(2) (100%), N(2) (100%), or 25% CO(2)/75% N(2) packaged sausage were irradiated at 0, 5, and 10 kGy, and residual nitrite, residual ascorbic acid, nitrosomyoglobin (NO-Mb), color values, and their correlation were observed. Irradiation significantly reduced the residual nitrite content and caused partial reduction of NO-Mb during storage. No difference was observed in ascorbic acid content by irradiation. Irradiation decreased the Hunter color a value of sausage. CO(2) or CO(2)/N(2) packaging were more effective for reducing residual nitrite and inhibiting the loss of the red color of sausage compared to N(2) packaging. Results indicated that the proper combination of irradiation and modified atmosphere packaging could reduce the residual nitrite in sausage with minimization of color change.

  12. Radiation dosimetry by neutron or X ray fluorescence activation of residual silver in ionographic emulsions

    International Nuclear Information System (INIS)

    Heilmann, C.

    1987-01-01

    A global measuring technique which is sensitive enough to detect small silver contents in films for dosimetry applications is presented. The applications studied are neutron dosimetry by measuring residual silver due to recoil protons in developed emulsions and high dose dosimetry by the detection of photolytic silver in fixed emulsions. An individual fast neutron dosimeter which can be used in radiation protection was developed, along with an automatic data analysis and readout system. Application of this technique to the measurement of high radiation doses (100 to 1 million Gy) via the measurement of photolytic silver in fixed, but undeveloped, emulsions confirms the usefulness of the method [fr

  13. Type I and type II residual stress in iron meteorites determined by neutron diffraction measurements

    Science.gov (United States)

    Caporali, Stefano; Pratesi, Giovanni; Kabra, Saurabh; Grazzi, Francesco

    2018-04-01

    In this work we present a preliminary investigation by means of neutron diffraction experiment to determine the residual stress state in three different iron meteorites (Chinga, Sikhote Alin and Nantan). Because of the very peculiar microstructural characteristic of this class of samples, all the systematic effects related to the measuring procedure - such as crystallite size and composition - were taken into account and a clear differentiation in the statistical distribution of residual stress in coarse and fine grained meteorites were highlighted. Moreover, the residual stress state was statistically analysed in three orthogonal directions finding evidence of the existence of both type I and type II residual stress components. Finally, the application of von Mises approach allowed to determine the distribution of type II stress.

  14. FEM Analysis and Measurement of Residual Stress by Neutron Diffraction on the Dissimilar Overlay Weld Pipe

    International Nuclear Information System (INIS)

    Kim, Kang Soo; Lee, Ho Jin; Woo, Wan Chuck; Seong, Baek Seok; Byeon, Jin Gwi; Park, Kwang Soo; Jung, In Chul

    2010-01-01

    Much research has been done to estimate the residual stress on a dissimilar metal weld. There are many methods to estimate the weld residual stress and FEM (Finite Element Method) is generally used due to the advantage of the parametric study. And the X-ray method and a Hole Drilling technique for an experimental method are also usually used. The aim of this paper is to develop the appropriate FEM model to estimate the residual stresses of the dissimilar overlay weld pipe. For this, firstly, the specimen of the dissimilar overlay weld pipe was manufactured. The SA 508 Gr3 nozzle, the SA 182 safe end and SA376 pipe were welded by the Alloy 182. And the overlay weld by the Alloy 52M was performed. The residual stress of this specimen was measured by using the Neutron Diffraction device in the HANARO (High-flux Advanced Neutron Application ReactOr) research reactor, KAERI (Korea Atomic Energy Research Institute). Secondly, FEM Model on the dissimilar overlay weld pipe was made and analyzed by the ABAQUS Code (ABAQUS, 2004). Thermal analysis and stress analysis were performed, and the residual stress was calculated. Thirdly, the results of the FEM analysis were compared with those of the experimental methods

  15. Non-Destructive Measurement of Residual Strain in Connecting Rods Using Neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Ikeda, Tomohiro [Honda R& D; Bunn, Jeffrey R. [ORNL; Fancher, Christopher M. [ORNL; Seid, Alan [Honda R& D; Motani, Ryuta [Honda R& D; Matsuda, Hideki [Honda R& D; Okayama, Tatsuya [Honda R& D

    2018-04-01

    Increasing the strength of materials is effective in reducing weight and boosting structural part performance, but there are cases in where the residual strain generated during the process of manufacturing of high-strength materials results in a decline of durability. It is therefore important to understand how the residual strain in a manufactured component changes due to processing conditions. In the case of a connecting rod, because the strain load on the connecting rod rib sections is high, it is necessary to clearly understand the distribution of strain in the ribs. However, because residual strain is generally measured by using X-ray diffractometers or strain gauges, measurements are limited to the surface layer of the parts. Neutron beams, however, have a higher penetration depth than X-rays, allowing for strain measurement in the bulk material. The research discussed within this paper consists of non-destructive residual strain measurements in the interior of connecting rods using the 2nd Generation Neutron Residual Stress Mapping Facility (NRSF2) at Oak Ridge National Laboratory, measuring the Fe (211) diffraction peak position of the ferrite phase. The interior strain distribution of connecting rod, which prepared under different manufacturing processes, was revealed. By the visualization of interior strains, clear understandings of differences in various processing conditions were obtained. In addition, it is known that the peak width, which is also obtained during measurement, is suggestive of the size of crystallites in the structure; however the peak width can additionally be caused by microstresses and material dislocations.

  16. Residual Stress Distribution In Heat Affected Zone Of Welded Steel By Means Of Neutron Diffraction Method

    International Nuclear Information System (INIS)

    Fajar, Andika; Prasuad; Gunawan; Muslich, M. Rifai

    1996-01-01

    Three dimensional residual stress distribution in the heat affected zone of 10 mm thick welded steel by means of neutron diffraction technique has been measured. The results showed that the residual stress was distributed near the welded metal, namely within about 46,25 mm. The major tensile stresses occurred in the X-direction, and they attained a level greater than 2000 MPa through the position far away fram the weld. The tensile stresses in the Y and Z- directions lied between 500 and 1500 MPa, The results also suggest that the stress in the surface was greater than that in the middle of the sample

  17. Residual Stress Measurement of SiC tile/Al7075 Hybrid Composites by Neutron Diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jong Bok; Lee, Jun Ho; Hong, Soon Hyung; Ryu, Ho Jin [KAIST, Daejeon (Korea, Republic of); Lee, Sang Bok; Lee, Sang Kwan [Korea Institute of Materials Science, Changwon (Korea, Republic of); Muslihd, M. Rifai [Center for Advanced Materials Science and Technology, Tangerang (India)

    2016-05-15

    In this research, SiC which has low density, high compressive strength, and high elastic modulus was used to fabricate the armor plate. In addition, Al which has low density and high toughness was used for a metal matrix of the composites. If two materials are combined, the composite can be effective materials for light weight armor applications. However, the existence of a large difference in coefficients of thermal expansion (CTE) between SiC and Al matrix, SiC/Al composites can have residual stresses while cooled in the fabrication process. Previous research reported that residual stresses in the composites or microstructures have an effect on the fatigue life and their mechanical properties. Some researchers reported about the residual stresses in the SiCp/Al metal matrix composites by numerical simulation systems, X-ray diffraction, and destructive methods. In order to analyze the residual stress of SiC/Al composites, the neutron diffraction as the non-destructive method was performed in this research. The 50 vol.% SiC{sub p}/Al7075 composites and SiC tile inserted 50 vol.% SiC{sub p}/Al7075 hybrid composites were measured to analyze the residual stress of Al (111) and SiC (111). Both samples had the tensile residual stresses in the Al (111) and the compressive residual stresses in the SiC (111) due to the difference in CTE.

  18. Neutron and ultrasonic determination of residual stress in an aluminum ring-plug

    International Nuclear Information System (INIS)

    Prask, H.J.; Gnaeupel-Herold, T.; Clark, A.V.; Hehman, C.S.; Nguyen, T.N.

    2000-01-01

    Stress is a principal cause of material failure. This has been a well-recognized problem for decades, yet--in general--neutron diffraction remains the only way to measure sub-surface residual stresses without destroying the component. A field-portable ultrasonic strain-meter is being developed at NIST (Boulder) to determine residual stresses in engineering specimens, nondestructively. To test this and other techniques an array of stress-measurement standards are being prepared. These will be characterized by neutron diffraction and then used to evaluate, quantitatively, the potential of new methods. The first standard specimen produced for this purpose is a large shrink-fit ring-plug of 2024 aluminum (305 mm OD, 25.4 mm thick, 101.6 mm diameter plug). Because of large grain size, a sample-rotation averaging technique was developed to make reliable neutron measurements possible. A comparison of the neutron diffraction and ultrasonic results for this specimen will be presented, along with strain gauge results

  19. STUDY OF THE THERMAL CRACKING DURING THE VACUUM DISTILLATION OF ATMOSPHERIC RESIDUE OF CRUDE OIL

    Directory of Open Access Journals (Sweden)

    JAOUAD ELAYANE

    2017-03-01

    Full Text Available This article concerns the study of the thermal cracking as undesirable phenomenon in the vacuum distillation of atmospheric residue of crude oil. In this point, we have sought to identify and characterize the effect of the increase in the temperature of vacuum distillation on the separation and the modification of the constituents of atmospheric residue of crude oil whose origin is Arabian Light. This study has been carried out by several techniques of analysis such as the density (ASTM D4052, distillation (ASTM D1160, determination of heavy metals nickel and vanadium (IFP9422, dosing of Conradson Carbon (ASTM D189, dosing of asphaltenes (ASTM D2549 and dosage of PCI (polycyclic aromatics (ASTM D 5186. The results showed a clear idea on the decomposition of the atmospheric residue and their influence on the performance of the vacuum distillation unit.

  20. Residual stress measurement of large scaled welded pipe using neutron diffraction method. Effect of SCC crack propagation and repair weld on residual stress distribution

    International Nuclear Information System (INIS)

    Suzuki, Hiroshi; Katsuyama, Jinya; Tobita, Tohru; Morii, Yukio

    2011-01-01

    The RESA-1 neutron engineering diffractometer in the JRR-3 (Japan Research Reactor No.3) at the Japan Atomic Energy Agency, which is used for stress measurements, was upgraded to realize residual stress measurements of large scaled mechanical components. A series of residual stress measurements was made to obtain through-thickness residual stress distributions in a Type 304 stainless steel butt-welded pipe of 500A-sch.80 using the upgraded RESA-1 diffractometer. We evaluated effects of crack propagation such as stress corrosion cracking (SCC) and a part-circumference repair weld on the residual stress distributions induced by girth welding. Measured residual stress distributions near original girth weld revealed good agreement with typical results shown in some previous works using finite element method, deep hole drilling as well as neutron diffraction. After introducing a mock crack with 10 mm depth in the heat affected zone on the inside wall of the pipe by electro discharge machining, the axial residual stresses were found to be released in the part of the mock crack. However, changes in the through-wall bending stress component and the self-equilibrated stress component were negligible and hence the axial residual stress distribution in the ligament was remained in the original residual stresses near girth weld without the mock crack. Furthermore, changes in hoop and radial residual stress were also small. The residual stress distributions after a part repair welding on the outer circumference of the girth weld were significantly different from residual stress distributions near the original girth weld. The through-thickness average axial residual stress was increased due to increase of the tensile membrane stress and mitigation of the bending stress after repair welding. Throughout above studies, we evidenced that the neutron diffraction technique is useful and powerful tool for measuring residual stress distributions in large as well as thick mechanical

  1. Model Atmospheres for X-ray Bursting Neutron Stars

    OpenAIRE

    Medin, Zach; von Steinkirch, Marina; Calder, Alan C.; Fontes, Christopher J.; Fryer, Chris L.; Hungerford, Aimee L.

    2016-01-01

    The hydrogen and helium accreted by X-ray bursting neutron stars is periodically consumed in runaway thermonuclear reactions that cause the entire surface to glow brightly in X-rays for a few seconds. With models of the emission, the mass and radius of the neutron star can be inferred from the observations. By simultaneously probing neutron star masses and radii, X-ray bursts are one of the strongest diagnostics of the nature of matter at extremely high densities. Accurate determinations of t...

  2. BOOK REVIEW: Analysis of Residual Stress by Diffraction Using Neutron and Synchrotron Radiation

    Science.gov (United States)

    Fitzpatrick, ed M. E.; Lodini, A.

    2003-09-01

    The presence of residual stresses within engineering components is often a key feature in determining their usable lifetimes and failure characteristics. Residual surface compression can, for example, restrict the propagation of surface cracks through the bulk. As a consequence, it is essential to characterize the magnitude and spatial distribution of residual stresses and, at least for non-destructive testing, this is most widely achieved using diffraction of neutron and high energy synchrotron radiations. This book aims to provide a detailed description of the methodology used to determine residual stresses. The major emphasis is placed on the neutron method, this being the more widely established approach at present. It contains 20 chapters contributed by 23 authors, divided into five major parts. The overall layout is very logical, with the first part giving a general introduction to the use of neutrons and x-rays for materials research and summarizing the methods used for their production. Part 2 considers the more specific aspects of extracting the residual stress distribution within a bulk sample and includes some valuable comments on a number of potential experimental problems, such as the determination of the stress-free lattice parameter and the effects of broadening of the Bragg peaks. The experimental facilities currently available or under development are described in part 3, with the remaining two parts devoted to general and specific applications of the residual stress measurement technique. As expected with such a large number of different authors, there is some variation in style and quality. However, the text is generally easy to follow and, more importantly, it is largely free of the problems of inconsistent notation and dupication of material that can afflict multi-authored texts. My only negative comment concerns the latter portion of the book devoted to specific applications of the technique, which is illustrative rather than comprehensive. In

  3. Residual stress analysis for engineering applications by means of neutron diffraction

    International Nuclear Information System (INIS)

    Gnaeupel-Herold, T.; Brand, P.C.; Prask, H.J.

    1999-01-01

    Residual stresses originate from spatial differences in plastic deformation, temperature, or phase distribution, introduced by manufacturing processes or during service. Engineering parts and materials experience mechanical, thermal, and chemical loads during their service, and most of these loads introduce stresses that are superimposed on the already existing residual stresses. Residual stresses can therefore limit or improve life and strength of engineering parts; knowledge and understanding of these stresses is therefore critical for optimizing strength and durability. The economic and scientific importance of neutron diffraction residual stress analysis has led to an increasing number of suitable instruments worldwide. All of the major sources due in the next several years will have instruments for the sole purpose of performing residual stress and texture measurements. Recently, a dedicated, state-of-the-art diffractometer has been installed at the National Institute of Standards and Technology reactor. It has been used for a variety of measurements on basic and engineering stress problems. Among the most prominent examples that have been investigated in collaboration with industrial and academic partners are residual stresses in rails, weldments, and plasma-sprayed coatings

  4. Discussion on accuracy of weld residual stress measurement by neutron diffraction. Influence of strain free reference

    International Nuclear Information System (INIS)

    Suzuki, Hiroshi; Akita, Koichi

    2012-01-01

    It is required to evaluate a strain-free reference, α 0 , to perform accurate stress measurement using neutron diffraction. In this study, accuracy of neutron stress measurement was quantitatively discussed from α 0 evaluations on a dissimilar metal butt-weld between a type 304 austenitic stainless steel and an A533B low alloy ferritic steel. A strain-free standard specimen and a sliced specimen with 10 mm thickness taken from the dissimilar metal butt-weld were utilized. In the lattice constant evaluation using the standard specimen, average lattice constant derived from multiple hkl reflections was evaluated as the stress-free reference with cancelling out an intergranular strain. Comparing lattice constant distributions in each reflection with average lattice constant distribution in the standard specimen, αFe211 and γFe311 reflections were judged as a suitable reflection for neutron strain measurement to reduce intergranular strain effects. Residual stress distribution in the sliced specimen evaluated using α 0 measured here exhibited higher accuracy than that measured using strain gauges. On the other hand, α 0 distributions were evaluated using the sliced specimen under the plane-stress condition. Existence of slight longitudinal residual stresses near the weld center decreased accuracy of the α 0 evaluations, which means that it is required to optimize the thickness of the sliced specimen for accurate α 0 evaluation under plane strain condition. As a conclusion of this study, it was confirmed that procedures of accurate α 0 evaluation, optimization of the measurement condition, and multiple evaluations on the results play an important role to improve accuracy of the residual stress measurement using neutron diffraction. (author)

  5. Internal residual strain mapping in carburized chrome molybdenum steel after quenching by neutron strain scanning

    International Nuclear Information System (INIS)

    Sakaida, Yoshihisa; Serizawa, Takanobu; Manzanka, Michiya

    2011-01-01

    A hollow circular cylinder specimen with an annular U-notch of chrome molybdenum steel with 0.20 mass% C (SCM420) was carburized in carrier gas and quenched in oil bath. In order to determine the case depth, the specimen was cut off and carbon content and Vickers hardness gradients were measured experimentally near the carburized surface. The residual strain mapping in the interior of carburized cylinder was conducted nondestructively by neutron strain scanning. In this study, the neutron diffraction from Fe-211 plane was used for strain scanning. The neutron wavelength was tuned to 0.1654nm so that diffraction angle became about 90deg. Radial, hoop and axial residual strains were measured by scanning diffracting volume along the axial direction of cylinder specimen. Each residual strain was calculated from lattice spacing change. Unstressed lattice spacing was determined experimentally using reference coupon specimens that were cut from the interior of same carburized cylinder. As a result, the diffraction peak width at half height, FWHM, near the carburized surface was about 3.7 times wider than that of coupon specimens. On the other hand, the most peak widths in the interior equaled to that of coupon specimens. Peak width broadened slightly as the diffracting volume approached the carburized case layer. From the center to the quarter of cylinder specimen, the hoop and axial strains were tensile, and the radial one was compressive in the interior. From the quarter to the edge of the cylinder specimen, the hoop tensile strain increased, radial and axial strains changed to tensile and compressive, respectively. Therefore, the interior of the cylinder specimen was found to be deformed elastically to balance the existence of compressive residual stresses in the carburized case layer. (author)

  6. Neutron-diffraction measurement of residual stresses in Al-Cu cold-cut welding

    CERN Document Server

    Fiori, F

    2002-01-01

    Usually, when it is necessary to join different materials with a large difference in their melting points, welding should be avoided. To overcome this problem we designed and built a device to obtain cold-cut welding, which is able to strongly decrease oxidation problems of the surfaces to be welded. Thanks to this device it is possible to achieve good joining between different pairs of materials (Al-Ti, Cu-Al, Cu-Al alloys) without reaching the material melting point. The mechanical and microstructural characterisation of the joining and the validation of its quality were obtained using several experimental methods. In particular, in this work neutron-diffraction experiments for the evaluation of residual stresses in Cu-Al junctions are described, carried out at the G5.2 diffractometer of LLB, Saclay. Neutron-diffraction results are presented and related to other experimental tests such as microstructural characterisation (through optical and scanning electron microscopy) and mechanical characterisation (ten...

  7. The determination of pesticide residues in local vegetables by means of neutron activation technique

    International Nuclear Information System (INIS)

    Mongkolphantha, S.; Karasuddhi, P.; Yamkate, P.; Serichareonsatit, N.

    1975-01-01

    Analytical methods based on neutron activation have been developed for studying pesticides residues of bromine, arsenic and mercury in local vegetables and fruits. The concentration of bromine, arsenic and mercury in samples are enriched prior to neutron irradiations by a technique of dry-ashing and freeze-drying for the determination of arsenic, bromine and mercury respectively. The element bromine is determined instrumentally while arsenic and mercury are determined destructively using a distillation technique. The limit of detection under the conditions used for bromine, arsenic and mercury as obtained are 0.01, 0.001 and 0.0001 microgram respectively. A total of 45 varieties of vegetables and 20 varieties of fruits are analyzed. The results of the investigation and the concentration range in part per million of bromine, arsenic and mercury are also presented

  8. Residual insufficiency of hematopoiesis after acute or chronic exposure to gamma radiation or neutrons

    International Nuclear Information System (INIS)

    Wangenheim, K.H. v.; Peterson, H.P.; Feinendegen, L.E.

    1983-01-01

    Recovery of the stem cell quality is possible after acute exposure to 500 rad γ radiation up to a period of 6 months. Beyond this data, a significant residual damage remains. The same applies to quantitative stem cell recovery. Chronic γ exposure leads to less radiation damage than acute exposure. After a total accumulation of 500 rad, the proliferation factors after chronic exposure were, on an average 20% higher than after acute radiation exposure. 6 MeV neutron exposure reduced the stem cell quality and stem cell count much more efficiently than γ exposure. The relative biological effect of neutrons is at least 2.5 times as high as the γ effect, both for the stem cell count and the stem cell quality. (orig.) [de

  9. Measurement of residual strain in composites by means of time-of- flight neutron diffraction

    International Nuclear Information System (INIS)

    Kupperman, D.S.; Majumdar, S.; Richardson, J.; Saigal, A.

    1993-01-01

    Neutron diffraction time-of-flight measurements using the Intense Pulsed Neutron Source at Argonne National Laboratory have been employed to study strain in various metal- and ceramic-matrix composites. For example, measurements carried out to 900 C on a composite composed of a titanium alloy matrix and silicon carbide fibers have been used to validate theoretical assumptions in the prediction of fabrication-induced residual stress. Sapphire reinforced nickel aluminide composites have also been studied. Studies of a high-temperature ceramic superconducting composite consisting of yttrium barium copper oxide and silver with various volume fractions of silver have also been carried out. The results of these studies have provided information on the effect of Ag content on interface bonding. In addition, ceramic-matrix composites with randomly dispersed ceramic whiskers with varying fiber content have been investigated

  10. Neutron diffraction measurements for the determination of residual stresses in MMC tensile and fatigue specimens

    DEFF Research Database (Denmark)

    Fiori, F.; Girardin, E.; Giuliani, A.

    2000-01-01

    have been performed at RISO (Roskilde, DK) and HMI-BENSC (Berlin, D), for the determination of residual stress in AA2124 + 17% SiCp and AA359 + 20% SiCp specimens, submitted to tensile and fatigue tests. For each of the investigated samples, the macrostress has been separated from the elastic......, residual stresses are present in both the matrix and the particles microstructure, prior to any macroscopic loading. They vary with the temperature and with the type and level of loading imposed to the material, having a strong influence on the mechanical behaviour of MMCs. Neutron diffraction measurements...... and thermal mismatch microstresses. The results show that, in general, the main contribution to the stress state of both matrix and reinforcement is given by the thermal microstresses, already existing due to heat treatment prior to mechanical tests. (C) 2000 Elsevier Science B.V. All rights reserved....

  11. Distribution patterns of firearm discharge residues as revealed by neutron activation analysis

    International Nuclear Information System (INIS)

    Pillay, K.K.S.; Driscoll, D.C.; Jester, W.A.

    1975-01-01

    A systematic investigation using a variety of handguns has revealed the existence of distinguisable distribution patterns of firearm discharge residues on surfaces below the flight path of a bullet. The residues are identificable even at distances of 12 meters from the gun using nondestructive neutron activation analysis. The results of these investigations show that the distribution pattern for a gun is reproducible using similar ammunition and that there exist two distinct regions to the patterns developed between the firearm and the target-one with respect to the position of the gun and the other in the vicinity of the target. The judicious applications of these findings could be of significant value in criminal investigations. (T.G.)

  12. Residual stress measurements in thick structural weldments by means of neutron diffraction

    International Nuclear Information System (INIS)

    Ohms, C.; Youtsos, A.G.; Idsert, P. v.d.; Timke, T.

    2000-01-01

    Welding residual stresses in large structural components are a major concern with respect to their performance and lifetime. In large structures reasonable thermal stress relief treatment is usually impossible due to the component size. On the other hand, prediction of welding stresses by numerical modelling has not yet proven to be generally reliable, while the experimental determination of such stresses remains a demanding task. At the high flux reactor (HFR), Petten, a new residual stress diffractometer has been installed recently capable of handling of components up to 1000 kg - the large component neutron diffraction facility (LCNDF). It has facilitated residual stress measurements in two large welded components, of which results are presented here. The first component represents a bi-metallic weld in form of a pipe of 25 mm wall thickness. Three dimensional measurements of residual stress are discussed in detail. The second specimen is a 66 mm wall thickness austenitic steel nuclear piping weld. Results on relief of strain within the weld through post weld heat treatment (PWHT) are presented. Additionally results obtained earlier at former CRNL (CAN) on a section of a thick nuclear piping weld are presented in order to illustrate the variation in the reference lattice parameter trough the weld and the heat affected zone (HAZ). These results clearly show the necessity to determine the reference parameters for each location in all measurement directions by means of measurements in small coupons free of macro-stresses. (orig.)

  13. Dosimetry of atmospheric neutrons: aircrew dosimetry and therapeutic applications

    International Nuclear Information System (INIS)

    Tatje, Jennifer

    2008-01-01

    This trainee-ship reports addresses the quantification of the dose received, in real time, by air-crews during commercial flights. Thus, the author first presents the radiative environment which surrounds people and components, and the possible consequences on this exposure. The different parameters influencing the received dose are developed and discussed. The author then describes the French SIEVERT calculation code which is used by all air companies. He also gives a detailed attention to the legal framework regarding radiation protection. In the next part, the author discusses the use of neutrons applied for therapeutic purposes, and their biological effects such as the bystander effect and the radio-sensitivity to low doses. He describes what is a cancer, and presents a therapeutic technique, the Boron Neutron Capture Therapy (BNCT), which is indicated for a certain type of brain cancer, the glioblastoma. The third part proposes an overview of the state-of-the-art of neutron dosimeters, and more particularly those doped with boron, for dose measurement

  14. Neutron stars

    International Nuclear Information System (INIS)

    Irvine, J.M.

    1978-01-01

    The subject is covered in chapters entitled: introduction (resume of stellar evolution, gross characteristics of neutron stars); pulsars (pulsar characteristics, pulsars as neutron stars); neutron star temperatures (neutron star cooling, superfluidity and superconductivity in neutron stars); the exterior of neutron stars (the magnetosphere, the neutron star 'atmosphere', pulses); neutron star structure; neutron star equations of state. (U.K.)

  15. Non-destructive neutron activation analysis of atmospheric pollutants

    International Nuclear Information System (INIS)

    Owlya, A.; Kasrai, M.; Massoumi, R.

    1976-01-01

    The concentration of elements in atmospheric particulate in an urban area were determined by means of a Ge(Li) detector. Samples were collected on a Millipore filter at a single location during three seasons of the year and the results compared. These results are compared with results for the same elements in other cities. It was concluded that in a dry climate, at least two parameters are related to seasonal changes in trace element concentration in the atmosphere-rain and snowfall, and the reducation of vertical diffusion of airborne particulates (author)

  16. Neutron diffraction measurements of residual stress in additively manufactured stainless steel

    International Nuclear Information System (INIS)

    Brown, D.W.; Bernardin, J.D.; Carpenter, J.S.; Clausen, B.; Spernjak, D.; Thompson, J.M.

    2016-01-01

    Charpy test specimens were additively manufactured (AM) on a single stainless steel plate from a 17–4 class stainless steel using a powder-bed, laser melting technique on an EOS M280 direct metal laser sintering (DMLS) machine. Cross-hatched mesh support structures for the Charpy test specimens were varied in strut width and density to parametrically study their influence on the build stability and accuracy as the DMLS process has been known to generate parts with large amounts of residual stress. Neutron diffraction was used to profile the residual stresses in several of the AM samples before and after the samples were removed from the support structure for the purpose of determining residual stresses. The residual stresses were found to depend very little on the properties of the support structure over the limited range studied here. The largest stress component was in the long direction of each of the samples studied and was roughly 2/3 of the yield stress of the material. The stress field was altered considerably when the specimen was removed from the support structure. It was noted in this study that a single Charpy specimen developed a significant tear between the growth plate and support structure. The presence of the tear in the support structure strongly affected the observed stress field: the asymmetric tear resulted in a significantly asymmetric stress field that propagated through removal of the sample from the base plate. The altered final residual stress state of the sample as well as its observed final shape indicates that the tear initiated during the build and developed without disrupting the fabrication process, suggesting a need for in-situ monitoring.

  17. Neutron diffraction measurements of residual stress in additively manufactured stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Brown, D.W.; Bernardin, J.D.; Carpenter, J.S.; Clausen, B.; Spernjak, D.; Thompson, J.M.

    2016-12-15

    Charpy test specimens were additively manufactured (AM) on a single stainless steel plate from a 17–4 class stainless steel using a powder-bed, laser melting technique on an EOS M280 direct metal laser sintering (DMLS) machine. Cross-hatched mesh support structures for the Charpy test specimens were varied in strut width and density to parametrically study their influence on the build stability and accuracy as the DMLS process has been known to generate parts with large amounts of residual stress. Neutron diffraction was used to profile the residual stresses in several of the AM samples before and after the samples were removed from the support structure for the purpose of determining residual stresses. The residual stresses were found to depend very little on the properties of the support structure over the limited range studied here. The largest stress component was in the long direction of each of the samples studied and was roughly 2/3 of the yield stress of the material. The stress field was altered considerably when the specimen was removed from the support structure. It was noted in this study that a single Charpy specimen developed a significant tear between the growth plate and support structure. The presence of the tear in the support structure strongly affected the observed stress field: the asymmetric tear resulted in a significantly asymmetric stress field that propagated through removal of the sample from the base plate. The altered final residual stress state of the sample as well as its observed final shape indicates that the tear initiated during the build and developed without disrupting the fabrication process, suggesting a need for in-situ monitoring.

  18. Residual Stresses in DC cast Aluminum Billet: Neutron Diffraction Measurements and Thermomechanical Modeling

    International Nuclear Information System (INIS)

    Drezet, J.-M.; Evans, A.; Pirling, T.

    2011-01-01

    Thermally-induced residual stresses, generated during the industrial Direct Chill casting process of aluminum alloys, can cause both significant safety concerns as well as the formation of defects during down-stream processing. Although these thermally induced strains can be partially relieved by permanent deformation, cracks will be generated either during solidification (hot tears) or post-solidification cooling (cold cracks) when stresses exceed the deformation limit of the alloy. Furthermore, the thermally induced strains result in the presence of large internal stresses within the billet before further processing steps. Although numerical models have been previously developed to compute these residual stresses, most of the computations have been validated only against measured surface distortions. In the present work, the variation in residual elastic strains and stresses in the steady state regime of casting has been measured as a function of radial position using neutron diffraction in an AA6063 grain-refined cylindrical billet. These measurements have been carried out on the same billet section at Poldi at PSI-Villigen and at Salsa at ILL-Grenoble and compare favorably. The results are used to validate a thermo-mechanical finite element casting model and to assess the level of stored elastic energy within the billet.

  19. Neutron star model atmospheres - a comparison with MXB 1728-34

    International Nuclear Information System (INIS)

    Foster, A.J.; Fabian, A.C.; Ross, R.R.

    1986-01-01

    A detailed comparison between the X-ray spectra calculated for model atmospheres in neutron stars and the observed spectra of X-ray bursts is presented. Comptonization and free - free absorption and emission processes are taken into account, as are the effects of iron in its last three states of ionization. Two types of model are formulated: (i) a constant density atmosphere and (ii) an atmosphere in approximate hydrostatic equilibrium. The models have been fitted to X-ray burst data obtained with EXOSAT from the source MXB 1728-34. It is possible simultaneously to fit a sub-Eddington burst luminosity, a neutron star radius consistent with current equations of state, and a distance in agreement with optical estimates. (author)

  20. Residual stress measurements by X-ray and neutron diffractions in heat-treated SiCw/A2014 composites

    International Nuclear Information System (INIS)

    Ohnuki, Takahisa; Fujita, Motoo; Tomota, Yo; Ono, Masayoshi

    1998-01-01

    Residual stresses due to various heat treatments in a 22 volume percent SiC whisker/A2014 metal matrix composite (MMC) were measured by using X-ray and neutron diffractions. Micro residual stresses generated from the differences in thermal expansion coefficients of the constituents and macro residual stresses associated with different cooling rates in the outer and inner regions of an MMC specimen must be distinguished in X-ray stress measurements. The conventional sin 2 ψ method under an assumption of plane stress condition has been found not to be applicable to the present MMC, because interactions among whiskers in the X-ray penetrating area yields σ 33 where the x 3 -axis is normal with respect to specimen's surface. An average value of σ 33 can be measured by X-ray diffraction technique, but does not seem enough to evaluate micro residual stresses. It is found that neutron diffraction is the most powerful method to measure micro residual stresses in the constituents. Elastic residual strains obtained by neutron diffraction in solution treated or T6 heat treated samples show good agreements with predictions calculated by using Eshelby inclusion theory coupled with the Mori-Tanaka mean field concept, indicating that the influence of stress relaxation is negligible. In addition, internal stresses relaxations during holding at room temperature, slow cooling from solution treatment temperature, or subzero cooling are discussed. (author)

  1. Residual stresses in a composite steel tube measured by neutron diffraction

    International Nuclear Information System (INIS)

    Taran, Yu.V.; Balagurov, A.M.; Zlokazov, V.B.; Schreiber, J.; Stuhr, U.; Kockelmann, H.

    2006-01-01

    The triaxial residual stresses in a composite tube from an austenitic stainless steel with a welded ferritic steel cladding were measured by the time-of-flight neutron diffraction method on the POLDI instrument at the PSI SINQ facility. The POLDI results are compared to the results obtained by the destructive turning out method and theoretical predictions of calculations by the finite element method. Only for the tangential component of the stress tensor the semiquantitative agreement of all used methods was observed. There is a clear discrepancy between the results of the different methods in the axial component. For the radial component all methods reveal quite small stresses, however, with some distinct differences in their distributions

  2. X-ray and neutron diffraction determination of residual stresses in a pressed and welded component

    International Nuclear Information System (INIS)

    Albertini, G.; Broda, M.; Fiori, F.; Girardin, E.; Giuliani, A.; Quadrini, E.

    1999-01-01

    Complete text of publication follows. Problems connected with welding and pressing are very important in mechanical design, as these processed create microstructural alterations and internal stresses in the material that cannot be neglected. A pressing steel (FEP13) machine element is considered, designed to support a scooter engine. Two kinds of fatigue are to be supported by the component during operation: high loads at low frequency, due to the interaction of the scooter with the soil and low loads at high frequency due to the engine. The knowledge of the residual stress field occurring before operation is fundamental in order to perform theoretical predictions of the stress state during operation, and also to determine the loads to be used in fatigue tests which the component will be submitted to. The results of X-ray and neutron experiments are presented, carried out across a 'critical' weld in the component. (author)

  3. Residual stress measurements via neutron diffraction of additive manufactured stainless steel 17-4 PH.

    Science.gov (United States)

    Masoomi, Mohammad; Shamsaei, Nima; Winholtz, Robert A; Milner, Justin L; Gnäupel-Herold, Thomas; Elwany, Alaa; Mahmoudi, Mohamad; Thompson, Scott M

    2017-08-01

    Neutron diffraction was employed to measure internal residual stresses at various locations along stainless steel (SS) 17-4 PH specimens additively manufactured via laser-powder bed fusion (L-PBF). Of these specimens, two were rods (diameter=8 mm, length=80 mm) built vertically upward and one a parallelepiped (8×80×9 mm 3 ) built with its longest edge parallel to ground. One rod and the parallelepiped were left in their as-built condition, while the other rod was heat treated. Data presented provide insight into the microstructural characteristics of typical L-PBF SS 17-4 PH specimens and their dependence on build orientation and post-processing procedures such as heat treatment. Data have been deposited in the Data in Brief Dataverse repository (doi:10.7910/DVN/T41S3V).

  4. Residual stress measurements via neutron diffraction of additive manufactured stainless steel 17-4 PH

    Directory of Open Access Journals (Sweden)

    Mohammad Masoomi

    2017-08-01

    Full Text Available Neutron diffraction was employed to measure internal residual stresses at various locations along stainless steel (SS 17-4 PH specimens additively manufactured via laser-powder bed fusion (L-PBF. Of these specimens, two were rods (diameter=8 mm, length=80 mm built vertically upward and one a parallelepiped (8×80×9 mm3 built with its longest edge parallel to ground. One rod and the parallelepiped were left in their as-built condition, while the other rod was heat treated. Data presented provide insight into the microstructural characteristics of typical L-PBF SS 17-4 PH specimens and their dependence on build orientation and post-processing procedures such as heat treatment. Data have been deposited in the Data in Brief Dataverse repository (doi:10.7910/DVN/T41S3V.

  5. Neutron-diffraction measurement of residual stresses in Al-Cu cold-cut welding

    Science.gov (United States)

    Fiori, F.; Marcantoni, M.

    Usually, when it is necessary to join different materials with a large difference in their melting points, welding should be avoided. To overcome this problem we designed and built a device to obtain cold-cut welding, which is able to strongly decrease oxidation problems of the surfaces to be welded. Thanks to this device it is possible to achieve good joining between different pairs of materials (Al-Ti, Cu-Al, Cu-Al alloys) without reaching the material melting point. The mechanical and microstructural characterisation of the joining and the validation of its quality were obtained using several experimental methods. In particular, in this work neutron-diffraction experiments for the evaluation of residual stresses in Cu-Al junctions are described, carried out at the G5.2 diffractometer of LLB, Saclay. Neutron-diffraction results are presented and related to other experimental tests such as microstructural characterisation (through optical and scanning electron microscopy) and mechanical characterisation (tensile-strength tests) of the welded interface.

  6. Protonation states of histidine and other key residues in deoxy normal human adult hemoglobin by neutron protein crystallography

    International Nuclear Information System (INIS)

    Kovalevsky, Andrey; Chatake, Toshiyuki; Shibayama, Naoya; Park, Sam-Yong; Ishikawa, Takuya; Mustyakimov, Marat; Fisher, S. Zoe; Langan, Paul; Morimoto, Yukio

    2010-01-01

    Using neutron diffraction analysis, the protonation states of 35 of 38 histidine residues were determined for the deoxy form of normal human adult hemoglobin. Distal and buried histidines may contribute to the increased affinity of the deoxy state for hydrogen ions and its decreased affinity for oxygen compared with the oxygenated form. The protonation states of the histidine residues key to the function of deoxy (T-state) human hemoglobin have been investigated using neutron protein crystallography. These residues can reversibly bind protons, thereby regulating the oxygen affinity of hemoglobin. By examining the OMIT F o − F c and 2F o − F c neutron scattering maps, the protonation states of 35 of the 38 His residues were directly determined. The remaining three residues were found to be disordered. Surprisingly, seven pairs of His residues from equivalent α or β chains, αHis20, αHis50, αHis58, αHis89, βHis63, βHis143 and βHis146, have different protonation states. The protonation of distal His residues in the α 1 β 1 heterodimer and the protonation of αHis103 in both subunits demonstrates that these residues may participate in buffering hydrogen ions and may influence the oxygen binding. The observed protonation states of His residues are compared with their ΔpK a between the deoxy and oxy states. Examination of inter-subunit interfaces provided evidence for interactions that are essential for the stability of the deoxy tertiary structure

  7. Neutron and synchrotron measurements of residual strain in TIG welded aluminium alloy 2024

    International Nuclear Information System (INIS)

    Owen, R.A.; Preston, R.V.; Withers, P.J.; Shercliff, H.R.; Webster, P.J.

    2003-01-01

    Tungsten inert gas (TIG) welding is one method of joining aluminium alloys with potential application in the aerospace industry. However, for it to be seriously considered as an alternative to mechanical fasteners the interrelated problems of residual stress and distortion need to be addressed. In this paper neutron, laboratory and synchrotron X-ray diffraction methods are used to provide non-destructive information about the residual stress field in TIG-welded 2024 Al alloy. The results compare well despite the differing penetration and sampling volumes associated with each technique. It is found that the magnitudes of the tensile longitudinal stresses decrease along the plate due to progressive heating up of the plate ahead of the arc during welding, so that steady-state conditions are not achieved. Comparison of the data with a finite element model indicates that softening of the heat-affected region must be included to simulate the resulting stress field. The FE model is found to be in good agreement with the data especially in the vicinity of the weld slope-out

  8. Non-destructive measurement of residual stresses in U-0.8 wt.% Ti by neutron diffraction

    International Nuclear Information System (INIS)

    Salinas-Rodriguez, A.; Root, J.H.; Holden, T.M.; Macewen, S.R.; Ludtka, G.M.

    1990-01-01

    The macroscopic residual stress distribution in γ-quenched and stress levelled U-0.8wt% Ti alloy tubes was studied using neutron diffraction techniques. Residual strains were evaluated from the difference in d-spacings measured in the tubes and in small reference samples machined from each tube. Residual stresses were calculated with the isotropic bulk value of the elastic constraints for polycrystalline α-U. Quenching from the γ field resulted in a nearly equi-biaxial stress state at every point across the wall thickness of the tube. The magnitude of the radial stress was very small compared with that of the axial and hoop stresses which were compressive at the surfaces and tensile in the interior. Stress levelling relieved almost completely the hoop residual stress without affecting the radial stress. The axial residual stress becomes tensile through the wall thickness and remains constant at about 20% of its magnitude in the as-quenched condition

  9. Use of neutron activation analysis at the IBR-2 reactor for atmospheric monitoring

    International Nuclear Information System (INIS)

    Peresedov, V.F.; Ostrovnaya, T.M.; Strelkova, L.P.; Chinaeva, V.P.; Gundorina, S.F.

    1999-01-01

    The object of this work was the study of the possibilities of neutron activation analysis (NAA) for determination of elemental content of atmospheric aerosol. On examples of three Siberian regions it was shown that methodics of analysis allow to estimate the average level of suburban background (ALSB), scale of its regional, season and annual changes. Analysis of enrichment factors allows one to convince in presence of increased content of a row of heavy metals in atmospheric air of background regions what is the consequence of a global growing of technogenic impact

  10. Effects of atmospheric neutrons on advanced micro-electronic devices, standards and applications

    International Nuclear Information System (INIS)

    Leray, J.L.; Baggio, J.; Ferlet-Cavrois, V.; Flament, O.

    2005-01-01

    Since the 1980's, it is known that terrestrial cosmic rays, mainly reported as atmospheric neutrons, can penetrate the natural shielding of buildings, equipments and circuit package and induce soft errors in integrated circuits and breakdown of power devices. The high-energy neutron fluxes of interest, larger than 10 MeV, range between 10 particles/cm 2 /hour at sea level and 10 4 particles/cm 2 /hour at typical airplanes flight altitude of 30000 feet, with modulation due to solar flares. In the 1990's, the phenomenon has pervaded as a consequence of the road-map of electronic devices especially the down-scaling of transistor dimensions, the increase of signal bandwidth and the increase of the size of DRAM and SRAM memory, stand-alone or embedded on processors and system-on-chips. Failure-in-time and soft error rate became unacceptable. Test standards and design solutions have been proposed to maintain reliability of commercial products and improve those used in special high-reliability equipments such as avionic computers. The paper describes the atmospheric neutron flux, the effects in the main classes of devices and specific cases such as neutron induced single event upset observed in CMOS vs. CMOS/SOI and some mitigation issues. In this paper, a model called CCPM (critical cross-point model) is proposed to provide critical graphs of technology node sensitivity along the scaling trend of CMOS. (authors)

  11. Neutron activation analysis of the atmosphere content in the Central Asia south regions

    International Nuclear Information System (INIS)

    Niyazova, O.A.; Turaev, Eh.Yu.

    2001-01-01

    By the method of neutron activation analysis a atmospheric air elementary content of south regions of Uzbekistan and Turkmenistan during the 'Afghan' dust-storm were studied. Comparison with data for atmospheric air before nad after this phenomenon was carried out.It shown, that during the 'Afghan' dust-storm the elements concentration of Au, La, Na, Sm, Hg, Cs, Zn, Co is increased in to 3-4 times. Concentration of Sc and Fe is increasing into 8-9 times. In the atmosphere with the storm beginning the Ce and Cr elements are appealing, its are absent before the 'Afghan' dust-storm. The surprise result, that Br element in air during the dust storm is disappearing

  12. Residual Stress Analysis of Severe Plastic Deformed Materials using the Finite Element Method and the Neutron Diffraction Method

    International Nuclear Information System (INIS)

    Kang, Mi Hyun; Seong, Back Suck; Kim, Hyoung Seop

    2009-01-01

    Severe plastic deformation (SPD) is one of the most promising top-down techniques, moving towards industrialization to fabricate bulk ultrafine grain materials. The strain distribution and deformation behavior during the ECAP (equal channel angular pressing), influenced by tool angles, friction and material behavior, was studied through experimental and numerical analyses. The residual stress of work piece which was straight before ECAP produces many serious problems in the next processing e.g. input of the work piece for the next ECAP. The bent work piece needs additional straightening or surface polishing even if the amount of bending is small, and residual stress need to be released before service applications. Residual stress, particularly tensile residual stress can be a very important factor in affecting the reliability and integrity of working parts. The formation of tensile residual stress may result in initiation of fatigue cracks, stress corrosion cracking, or other types of fracture. Hence, residual stress and resulting bending need to be controlled during ECAP. Thus, in current study the bending behavior and the residual stress of the work piece in ECAP are analyzed through experimental and finite element analyses by considering the effects of material, geometric, and processing parameters individually. The stress states in the ECAP processed work piece were measured by the non-destructive way using neutron diffraction. Efforts were made to suggest the alternate routes to reduce the residual stress and bending of work piece in ECAP

  13. Development of a phoswich detector for neutron dose rate measurements in the Earth's atmosphere

    International Nuclear Information System (INIS)

    Doensdorf, Esther Miriam

    2014-01-01

    The Earth is constantly exposed to a stream of energetic particles from outer space. Through the interaction of this radiation with the Earth's magnetosphere and atmosphere a complex radiation field is formed which varies with the location inside the Earth's atmosphere. This radiation field consists of charged and uncharged particles leading to the constant exposure of human beings to radiation. As this ionizing radiation can be harmful for humans, it is necessary to perform dose rate measurements in different altitudes in the Earth's atmosphere. Due to their higher biological effectiveness the exposure to neutrons is more harmful than the exposure to γ-rays and charged particles, which is why the determination of neutron dose rates is the focus of this work. In this work the prototype of a Phoswich detector called PING (Phoswich Instrument for Neutrons and Gammas) is developed to determine dose rates caused by neutrons in the Earth's atmosphere and to distinguish these from γ-rays. The instrument is composed of two different scintillators optically coupled to each other and read out by one common photomultiplier tube. The scintillator package consists of an inner plastic scintillator made of the material BC-412 and a surrounding anti-coincidence made of sodium doped caesium iodide (CsI(Na)). In this work the instrument is calibrated, tested and flown and a procedure for a pulse shape analysis for this instrument is developed. With this analysis it is possible to distinguish pulses from the plastic scintillator and pulses from the CsI(Na). The pulses from the plastic scintillator are mainly due to the interaction of neutrons but there is an energy-dependent contribution of γ-rays to these events. Measurements performed on board an airplane show that the dose rates measured with the developed detector are in the same order of magnitude as results of other instruments. During measurements on board stratospheric balloons the altitude dependence of count rates and

  14. Effects of the residual proton-neutron interaction in the development of collectivity in nuclei

    International Nuclear Information System (INIS)

    Casten, R.F.

    1990-01-01

    The widespread effects of the residual T=0 proton-neutron (p-n) interaction in the evolution of nuclear structure are discussed. Although these effects in inducing single nucleon configuration mixing, and hence in the development of non-spherical nuclear shapes, collectivity, and the associated shape and phase transitions have been known for four decades, it is only in recent years that their deep ramifications have become more fully appreciated. This had led to a unified phenomenological understanding of the role of the p-n interaction in nuclear collectivity and to, for example, the proposal of the N p N n scheme and the associated concept of the P factor, which is a normalized value of N p N n reflecting the average number of p-n interactions per valence nucleon. Simultaneously, experimentally-determined p-n matrix elements for many nuclei have been extracted: they disclose striking anomalies for N=Z nuclei, and intriguing microstructure. These developments and empirical results will be discussed along with microscopic calculations that can be used to interpret them. 18 refs., 13 figs

  15. Determination of barium and antimony in gun shot residues by neutron activation analysis

    International Nuclear Information System (INIS)

    Charuchinda, A.

    1975-01-01

    The antimony contents on both hands of 7 persons before and after firing an automatic pistol were determined by instrumental neutron activation analysis. The gun shot residues were removed from hands by a 4% solution of cellulose acetate in acetone. The average content of antimony on both hands before firing obtained from 70 measurements (35 from each hand) was 0.040 ± 0.010 micro gram, whereas the average contents on the right and the left hands after 1 firing were 0.385 ± 0.036 and 0.144 ± 0.029 micro gram respectively. The ration of the antimony contents after 1 firing to the normal level (before firing) was 9.9 for the right and 3.6 for the left. No significant difference was observed between male and female, smoker and non-smoker. The antimony content after several firings was not much different from that of 1 firing and it reduced to the normal level within 2 days after firing. The barium contents before and after firing were studied from one person. Barium was precipitated as Ba SO 4 before counting. An average contents of 0.936 ± 0.551 micro gram for both hands before firing, 4.092 ± 2.687 micro gram for the right hand and 1.363 ± 0.879 micro gram for the left hand after 1 firing were found

  16. Net emissions of carbon dioxide to the atmosphere when using forest residues for production of heat and electricity

    International Nuclear Information System (INIS)

    Zetterberg, L.; Hansen, O.

    1998-05-01

    This study estimates net emissions of carbon dioxide to the atmosphere from the use of forest residues for production of heat and electricity. In the report, the use of forest residues for energy production is called residue-usage. Our results show that for a turnover period of 80 years, the net emission of CO 2 to the atmosphere is 15.8 kg CO 2 -C/MWh (3.1-31.6 kg CO 2 -C/MWh), which represents 16% of the total carbon content in the wood fuel (3%-32%). Fossil fuel consumption is responsible for 3.1 kg CO 2 -C/MWh of this. Residue-usage may produce indirect emissions or uptake of carbon dioxide, e.g. through changes in production conditions, changes in the turnover of carbon in the humus layer or through a reduction of the amount of forest fires. Due to uncertainties in data it is hard to quantify these indirect effects. In some cases it is hard even to determine their signs. As a consequence of this, we have chosen not to include the indirect effects in our estimates of net emissions from residue-usage. Instead we discuss these effects in a qualitative manner. It may seem surprising that the biogenic part of the residue-usage produces a net emission of carbon dioxide considering that carbon has originated from the atmosphere. The explanation is that the residue-usage systematically leads to earlier emissions than would be the case if the residues were left on the ground. If forest residues are left to decay, in the long run a pool of carbon might be created in the ground. This does not happen with residue-usage 33 refs, 4 figs, 12 tabs

  17. Cosmic Rays and Clouds, 1. Formation of Lead Mesoatoms In Neutron Monitor By Soft Negative Muons and Expected Atmospheric Electric Field Effect In The Cosmic Ray Neutron Component

    Science.gov (United States)

    Dorman, L. I.; Dorman, I. V.

    We extend our model (Dorman and Dorman, 1995) of cosmic ray atmospheric electric field effect on the case of neutron monitor. We take into account that about 0.07 of neu- tron monitor counting rate caused by negative soft muons captured by lead nucleons and formed mesoatoms with generation of several MeV energy neutrons from lead. In this case the neutron monitor or neutron supermonitor works as analyzer which de- tects muons of only one, negative sign. It is very important because the atmospheric electric field effect have opposite signs for positive and negative muons that main part of this effect in the muon telescope or in ionization chamber is compensated and we can observe only small part of total effect of one sign muons. On the basis of our gen- eral theory of cosmic ray meteorological effects with taking into account of negative soft muon acceleration and deceleration in the Earth atmosphere (in dependence of di- rection and intensity of electric field) we discuss the possibility of existing this effect in cosmic ray neutron component and made some rough estimations. REFERENCES: Dorman L.I. and Dorman I.V., 1995. "Cosmic-ray atmospheric electric field effects". Canadian J. of Physics, Vol. 73, pp. 440-443.

  18. Impact of agriculture crop residue burning on atmospheric aerosol loading – a study over Punjab State, India

    Directory of Open Access Journals (Sweden)

    Darshan Singh

    2010-02-01

    Full Text Available The present study deals with the impact of agriculture crop residue burning on aerosol properties during October 2006 and 2007 over Punjab State, India using ground based measurements and multi-satellite data. Spectral aerosol optical depth (AOD and Ångström exponent (α values exhibited larger day to day variation during crop residue burning period. The monthly mean Ångström exponent "α" and turbidity parameter "β" values during October 2007 were 1.31±0.31 and 0.36±0.21, respectively. The higher values of "α" and "β" suggest turbid atmospheric conditions with increase in fine mode aerosols over the region during crop residue burning period. AURA-OMI derived Aerosol Index (AI and Nitrogen dioxide (NO2 showed higher values over the study region during October 2007 compared to October 2006 suggesting enhanced atmospheric pollution associated with agriculture crop residue burning.

  19. Two-quasineutron states in 98248Cf and 98250Cf and the neutron-neutron residual interactions

    International Nuclear Information System (INIS)

    Katori, K.; Ahmad, I.; Friedman, A. M.

    2008-01-01

    Two-quasineutron states in 248 Cf and 250 Cf were investigated by single-neutron transfer reactions, 249 Cf(d,t) 248 Cf and 249 Cf(d,p) 250 Cf. The majority of levels observed were assigned to 12 bands in 248 Cf and six bands in 250 Cf, constructed from the single-particle states in neighboring Cf nuclei. The effective two-body interactions between two odd neutrons coupled outside a deformed core were deduced from the differences in the energies of the bandheads formed by the parallel and antiparallel coupling of the intrinsic spins of the two single-particle states

  20. Magnetic Hydrogen Atmosphere Models and the Neutron Star RX J1856.5-3754

    Energy Technology Data Exchange (ETDEWEB)

    Ho, Wynn C.G.; /MIT, MKI /KIPAC, Menlo Park; Kaplan, David L.; /MIT, MKI; Chang, Philip; /UC, Berkeley, Astron. Dept. /UC, Santa Barbara; van Adelsberg, Matthew; /Cornell; Potekhin, Alexander Y.; /Cornell U., Astron. Dept. /Ioffe Phys. Tech. Inst.

    2006-12-08

    RX J1856.5-3754 is one of the brightest nearby isolated neutron stars, and considerable observational resources have been devoted to it. However, current models are unable to satisfactorily explain the data. We show that our latest models of a thin, magnetic, partially ionized hydrogen atmosphere on top of a condensed surface can fit the entire spectrum, from X-rays to optical, of RX J1856.5-3754, within the uncertainties. In our simplest model, the best-fit parameters are an interstellar column density N{sub H} {approx} 1 x 10{sup 20} cm{sup -2} and an emitting area with R{sup {infinity}} {approx} 17 km (assuming a distance to RX J1856.5-3754 of 140 pc), temperature T{sup {infinity}} {approx} 4.3 x 10{sup 5} K, gravitational redshift z{sub g} {approx} 0.22, atmospheric hydrogen column y{sub H} {approx} 1 g cm{sup -2}, and magnetic field B {approx} (3-4) x 10{sup 12} G; the values for the temperature and magnetic field indicate an effective average over the surface. We also calculate a more realistic model, which accounts for magnetic field and temperature variations over the neutron star surface as well as general relativistic effects, to determine pulsations; we find there exist viewing geometries that produce pulsations near the currently observed limits. The origin of the thin atmospheres required to fit the data is an important question, and we briefly discuss mechanisms for producing these atmospheres. Our model thus represents the most self-consistent picture to date for explaining all the observations of RX J1856.5-3754.

  1. Residual stress analysis in linear friction welded in-service Inconel 718 superalloy via neutron diffraction and contour method approaches

    Energy Technology Data Exchange (ETDEWEB)

    Smith, M. [University of British Columbia – Okanagan, School of Engineering, 3333 University Way, Kelowna, Canada V1V 1V7 (Canada); Levesque, J.-B. [Institut de recherche d' Hydro-Québec (IREQ), 1800 Lionel-Boulet Blvd., Varennes, Canada J3X 1S1 (Canada); Bichler, L., E-mail: lukas.bichler@ubc.ca [University of British Columbia – Okanagan, School of Engineering, 3333 University Way, Kelowna, Canada V1V 1V7 (Canada); Sediako, D. [Canadian Nuclear Laboratories, Building 459, Station 18, Chalk River, Canada K0J 1J0 (Canada); Gholipour, J.; Wanjara, P. [National Research Council of Canada, Aerospace 5145 Decelles Ave., Montreal, Canada H3T 2B2 (Canada)

    2017-04-13

    In this study, an analysis of elastic residual stress in Inconel{sup ®} 718 (IN 718) linear friction welds (LFWs) was carried out. In particular, the suitability of LFW for manufacturing and repair of aero engine components was emulated by joining virgin and in-service (extracted from a turbine disk) materials. The evolution in the residual strains and stresses in the heat-affected zone (HAZ), thermomechanically affected zone (TMAZ) and dynamically recrystallized zone (DRX) of the weld was characterized using the neutron diffraction and contour methods. The results provided insight into diverse challenges in quantitative analysis of residual stresses in welded IN 718 using diffraction techniques. Specifically, judicious selection of the beam width, height and stress-free lattice spacing were seen to be crucial to minimize measurement error and increase accuracy. Further, the contour method – a destructive technique relying on capturing the stress relaxation after electrical discharge machining – was used to characterize the residual stress distribution on two-dimensional plane sections of the welds. Both techniques suggested an increasing magnitude of residual stress originating from the base metal that reached a peak at the weld interface. Both methods indicated that the peak magnitude of residual stresses were below the yield stress of IN 718.

  2. Residual strain dependence on the matrix structure in RHQ-Nb3Al wires by neutron diffraction measurement

    International Nuclear Information System (INIS)

    Jin Xinzhe; Nakamoto, Tatsushi; Tsuchiya, Kiyosumi; Ogitsu, Toru; Yamamoto, Akira; Ito, Takayoshi; Harjo, Stefanus; Kikuchi, Akihiro; Takeuchi, Takao; Hemmi, Tsutomu

    2012-01-01

    We prepared three types of non-Cu RHQ-Nb 3 Al wire sample with different matrix structures: an all-Ta matrix, a composite matrix of Nb and Ta with a Ta inter-filament, and an all-Nb matrix. Neutron diffraction patterns of the wire samples were measured at room temperature in the J-PARC ‘TAKUMI’. To obtain the residual strains of the materials, we estimated the lattice constant a by multi-peak analysis in the wires. A powder sample of each wire was measured, where the powder was considered to be strain free. The grain size of all the powder samples was below 0.02 mm. For the wire sample with the all-Nb matrix, we also obtained the lattice spacing d by a single-peak analysis. The residual strains of the Nb 3 Al filament were estimated from the two analysis results and were compared. The resulting residual strains obtained from the multi-peak analysis showed a good accuracy with small standard deviation. The multi-peak analysis results for the residual strains of the Nb 3 Al filaments in the three samples (without Cu plating) were all tensile residual strain in the axial direction, of 0.12%, 0.12%, and 0.05% for the all-Ta matrix, the composite matrix, and the all-Nb matrix, respectively. The difference in the residual strain of the Nb 3 Al filament between the composite and all-Nb matrix samples indicates that the type of inter-filament material shows a great effect on the residual strain. In this paper, we report the method of measurement, method of analysis, and results for the residual strain in the three types of non-Cu RHQ-Nb 3 Al wires. (paper)

  3. Determination of residual oil saturation from time-lapse pulsed neutron capture logs in a large sandstone reservoir

    International Nuclear Information System (INIS)

    Syed, E.V.; Salaita, G.N.; McCaffery, F.G.

    1991-01-01

    Cased hole logging with pulsed neutron tools finds extensive use for identifying zones of water breakthrough and monitoring oil-water contacts in oil reservoirs being depleted by waterflooding or natural water drive. Results of such surveys then find direct use for planning recompletions and water shutoff treatments. Pulsed neutron capture (PNC) logs are useful for estimating water saturation changes behind casing in the presence of a constant, high-salinity environment. PNC log surveys run at different times, i.e., in a time-lapse mode, are particularly amenable to quantitative analysis. The combined use of the original open hole and PNC time-lapse log information can then provide information on remaining or residual oil saturations in a reservoir. This paper reports analyses of historical pulsed neutron capture log data to assess residual oil saturation in naturally water-swept zones for selected wells from a large sandstone reservoir in the Middle East. Quantitative determination of oil saturations was aided by PNC log information obtained from a series of tests conducted in a new well in the same field

  4. A neutron diffraction study of residual stress and plastic strain in welded beryllium rings

    Energy Technology Data Exchange (ETDEWEB)

    Brown, D.W.; Varma, R.; Bourke, M.A.M.; Holden, T.M. [Los Alamos National Lab., Los Alamos, NM (United States); Ely, T.; Spooner, S. [Oak Ridge National Lab., Oak Ridge, TN (United States)

    2002-07-01

    We present a study of residual stresses associated with the welding of beryllium rings. Using novel analysis techniques, information about residual stresses and plastic deformation of the base metal were obtained. In the post-welded state, the rings have a strong tensile circumferential residual stress and show evidence of significant plastic deformation. (orig.)

  5. Residual stress analysis by neutron time-of-flight at a reactor source

    International Nuclear Information System (INIS)

    Priesmeyer, H.G.; Schroder, J.

    1990-01-01

    Non-destructive neutron diffractometry for stress analysis will be a powerful experimental tool in material science research performed at the GKSS 5 MW reactor FRG-1. Arguments which show the advantages of the time-of-flight method are given and a suitable high-resolution neutron-efficient type of spectrometer is introduced. First results derived from this method are presented

  6. The use of neutron diffraction for the determination of the in-depth residual stresses profile in weld coatings

    International Nuclear Information System (INIS)

    Marques, Maria Jose; Batista, A.C.; Nobre, J.P.; Loureiro, Altino; Kornmeier, Joana R.

    2013-01-01

    The neutron diffraction is a non-destructive technique, particularly suitable for the analysis of residual stress fields in welds. The technique is used in this article to study ferritic samples, coated by submerged arc welding using stainless steel filler metals. This procedure is often used for manufacturing process equipment for chemical and nuclear industries, for ease of implementation and economic reasons. The main disadvantage of that processes is the cracking phenomenon that often occurs at the interface between the base material and coatings, which can be minimized by performing post-weld stress relief heat treatments. The samples analyzed in this study were made of carbon steel plates, coated by submerged arc welding two types of stainless steel filler metals. For the first layer was used one EN 12 072 - S 2 U 23 12 electrode, while for the second and third layers were used an EN 12 072 - 19 12 3 S L electrode. After cladding, the samples were submitted to a post-weld heat treatment for 1 hour at 620 deg C. The residual stress profiles obtained by neutron diffraction evidence the relaxation of residual stress given by the heat treatment. (author)

  7. Atmospheres and spectra of strongly magnetized neutron stars - II. The effect of vacuum polarization

    Science.gov (United States)

    Ho, Wynn C. G.; Lai, Dong

    2003-01-01

    We study the effect of vacuum polarization on the atmosphere structure and radiation spectra of neutron stars with surface magnetic fields B= 1014-1015 G, as appropriate for magnetars. Vacuum polarization modifies the dielectric property of the medium and gives rise to a resonance feature in the opacity; this feature is narrow and occurs at a photon energy that depends on the plasma density. Vacuum polarization can also induce resonant conversion of photon modes via a mechanism analogous to the Mikheyev-Smirnov-Wolfenstein (MSW) mechanism for neutrino oscillation. We construct atmosphere models in radiative equilibrium with an effective temperature of a few ×106 K by solving the full radiative transfer equations for both polarization modes in a fully ionized hydrogen plasma. We discuss the subtleties in treating the vacuum polarization effects in the atmosphere models and present approximate solutions to the radiative transfer problem which bracket the true answer. We show from both analytic considerations and numerical calculations that vacuum polarization produces a broad depression in the X-ray flux at high energies (a few keV <~E<~ a few tens of keV) as compared to models without vacuum polarization; this arises from the density dependence of the vacuum resonance feature and the large density gradient present in the atmosphere. Thus the vacuum polarization effect softens the high-energy tail of the thermal spectrum, although the atmospheric emission is still harder than the blackbody spectrum because of the non-grey opacities. We also show that the depression of continuum flux strongly suppresses the equivalent width of the ion cyclotron line and therefore makes the line more difficult to observe.

  8. Effects of neutron radiation and residual stresses on the corrosion of welds in light water reactor internals

    International Nuclear Information System (INIS)

    Schaaf, Bob van der; Gavillet, Didier; Lapena, Jesus; Ohms, Carsten; Roth, Armin; Dyck, Steven van

    2006-01-01

    After many years of operation in Light Water Reactors (LWR) Irradiation Assisted Stress Corrosion Cracking (IASCC) of internals has been observed. In particular the heat-affected zone (HAZ) has been associated with IASCC attack. The welding process induces residual stresses and micro-structural modifications. Neutron irradiation affects the materials response to mechanical loading. IASCC susceptibility of base materials is widely studied, but the specific conditions of irradiated welds are rarely assessed. Core component relevant welds of Type 304 and 347 steels have been fabricated and were irradiated in the High Flux Reactor (HFR) in Petten to 0.3 and 1 dpa (displacement per atom). In-service welds were cut from the thermal shield of the decommissioned BR-3 reactor. Residual stresses, measured using neutron diffraction, ring core tests and X-ray showed residual stress levels up to 400 MPa. Micro-structural characterization showed higher dislocation densities in the weld and HAZ. Neutron radiation increased the dislocation density, resulting in hardening and reduced fracture toughness. The sensitization degree of the welds, measured with the electrochemical potentio-dynamic reactivation method, was negligible. The Slow Strain Rate Tensile (SSRT) tests, performed at 290 deg. C in water with 200 ppb dissolved oxygen, (DO), did not reveal inter-granular cracking. Inter-granular attack of in-service steel is observed in water with 8 ppm (DO), attributed not only to IASCC, but also to IGSCC from thermal sensitization during fabrication. Stress-relieve annealing has caused Cr-grain boundary precipitation, indicating the sensitization. The simulated internal welds, irradiated up to 1.0 dpa, did not show inter-granular cracking with 8 ppm DO. (authors)

  9. Neutron Diffraction Residual Strain Tensor Measurements Within The Phase IA Weld Mock-up Plate P-5

    Energy Technology Data Exchange (ETDEWEB)

    Hubbard, Camden R [ORNL

    2011-09-01

    Oak Ridge National Laboratory (ORNL) has worked with NRC and EPRI to apply neutron and X-ray diffraction methods to characterize the residual stresses in a number of dissimilar metal weld mockups and samples. The design of the Phase IA specimens aimed to enable stress measurements by several methods and computational modeling of the weld residual stresses. The partial groove in the 304L stainless steel plate was filled with weld beads of Alloy 82. A summary of the weld conditions for each plate is provided in Table 1. The plates were constrained along the long edges during and after welding by bolts with spring-loaded washers attached to the 1-inch thick Al backing plate. The purpose was to avoid stress relief due to bending of the welded stainless steel plate. The neutron diffraction method was one of the methods selected by EPRI for non-destructive through thickness strain and stress measurement. Four different plates (P-3 to P-6) were studied by neutron diffraction strain mapping, representing four different welding conditions. Through thickness neutron diffraction strain mappings at NRSF2 for the four plates and associated strain-free d-zero specimens involved measurement along seven lines across the weld and at six to seven depths. The mountings of each plate for neutron diffraction measurements were such that the diffraction vector was parallel to each of the three primary orthogonal directions of the plate: two in-plane directions, longitudinal and transverse, and the direction normal to the plate (shown in left figure within Table 1). From the three orthogonal strains for each location, the residual stresses along the three plate directions were calculated. The principal axes of the strain and stress tensors, however, need not necessarily align with the plate coordinate system. To explore this, plate P-5 was selected for examination of the possibility that the principal axes of strain are not along the sample coordinate system axes. If adequate data could

  10. Bromine determination by neutron activation analysis and its distribution in the atmosphere

    International Nuclear Information System (INIS)

    Iturbe Garcia, J.L.; Lopez Munoz, B.E.

    2002-01-01

    Bromine, one of the main participants in ozone layer destruction, is 10 to 100 times more effective than chlorine. There are two principal sources of methyl bromide emissions: the oceans and some pesticides that are used in farming. Bromine was detected in 'premium' and 'magna sin' gasolines (2.86±0.96 and 1.54±0.38 ppm, respectively) as well as in condensed water found in exhaust pipes of vehicles. In addition, samples of rainwater were also analyzed to determine atmospheric bromine concentration. In water samples Br concentrations ranging from 2.09 to 0.06 ppm were found. The techniques utilised were neutron activation analysis and high voltage electrophoresis, the latter to determine the chemical form of bromine in condensed water samples. Finally, suspended particles from rainwater were also analysed by scanning electron microscopy (SEM). (author)

  11. Multielement characterization of atmospheric pollutants by x-ray fluorescence analysis and instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Rancitelli, L.A.; Tanner, T.M.

    1976-01-01

    The simultaneous measurement of a wide spectrum of elements in aerosols collected on air filters and in rainwater can yield information on the origin, transport, and removal of atmospheric pollutants. In order to determine the elemental content of these aerosols, a pair of highly sensitive, precise and complementing instrumental techniques, x-ray fluorescence and neutron activation analysis, have been developed and employed. Data are presented on the results of combined x-ray fluorescence and activation analysis of aerosols collected in a number of urban areas of the USA and from the 80th median sampling network in March 1972. From a comparison of these ratios in granite and diabase with those of filters placed in urban areas, it is evident that Zn, Se, Sb, Hg, and Pb levels have been increased by as much as several orders of magnitude. Al, Co, La, Fe, Eu, Sm, Tb, Ta, Hf, and Th appear to exist at levels compatible with an earth's crust origin

  12. The role of neutron activation analysis for trace elements characterization, analysis and certification in atmospheric particulates

    International Nuclear Information System (INIS)

    Rizzio, Enrico; Gallorini, Mario

    2002-01-01

    The Neutron Activation Analysis (NAA) owns these requirements and is universally accepted as one of the most reliable analytical tools for trace and ultratrace elements determination. Its use in trace elements atmospheric pollution related studies has been and is still extensive as can be demonstrate by several specific works and detailed reviews. In this work, the application of this nuclear technique, in solving a series of different analytical problems related to trace elements in air pollution processes is reported. Examples and results are given on the following topics: characterization of urban and rural airborne particulate samples; particles size distribution in the different inhalable and respirable fractions (PM10 and PM 2.5); certification of related Standard Reference Materials for data quality assurance. (author)

  13. Assessment of the effects of atmospheric neutrons on onboard electronic equipment and search for hardening solutions

    International Nuclear Information System (INIS)

    Renard, S.

    2013-01-01

    This work deals with the impact of atmospheric neutrons on complex electronic components such as built-in memories or processors. The first part describes the radiation environment, the neutron-matter interaction and the consequences on electronic devices, and presents the commonly used experimental simulations and the testing methods. The potential of laser beam for testing is highlighted. The second chapter presents the development of a testing platform for various types of memories (MRAM and SDRAM). The equipment and the dedicated software are described. A testing platform for processor is also presented. The third chapter is dedicated to the presentation of a 4 Mbit bulk-type SRAM memory and of its testing involving a laser beam equipment. Several results show the presence of error clusters that may endangered the memory as a whole. These error clusters are due to the architecture of the internal addressing scheme of the memory. The simulation of these error clusters must be improved in order to define an optimized strategy of hardening

  14. Effects of atmospheric neutrons on advanced micro-electronic devices, standards and applications; Effets des neutrons atmospheriques sur les dispositifs microelectroniques avances, normes et applications

    Energy Technology Data Exchange (ETDEWEB)

    Leray, J.L. [CEA, 75 - Paris (France); Baggio, J.; Ferlet-Cavrois, V.; Flament, O. [CEA Bruyeres-le-Chatel, 91 (France)

    2005-10-01

    Since the 1980's, it is known that terrestrial cosmic rays, mainly reported as atmospheric neutrons, can penetrate the natural shielding of buildings, equipments and circuit package and induce soft errors in integrated circuits and breakdown of power devices. The high-energy neutron fluxes of interest, larger than 10 MeV, range between 10 particles/cm{sup 2}/hour at sea level and 10{sup 4} particles/cm{sup 2}/hour at typical airplanes flight altitude of 30000 feet, with modulation due to solar flares. In the 1990's, the phenomenon has pervaded as a consequence of the road-map of electronic devices especially the down-scaling of transistor dimensions, the increase of signal bandwidth and the increase of the size of DRAM and SRAM memory, stand-alone or embedded on processors and system-on-chips. Failure-in-time and soft error rate became unacceptable. Test standards and design solutions have been proposed to maintain reliability of commercial products and improve those used in special high-reliability equipments such as avionic computers. The paper describes the atmospheric neutron flux, the effects in the main classes of devices and specific cases such as neutron induced single event upset observed in CMOS vs. CMOS/SOI and some mitigation issues. In this paper, a model called CCPM (critical cross-point model) is proposed to provide critical graphs of technology node sensitivity along the scaling trend of CMOS. (authors)

  15. Instrumental neutron activation analysis of dry atmospheric fall-out and rain-water

    International Nuclear Information System (INIS)

    Schutyser, P.; Maenhaut, W.; Dams, R.

    1978-01-01

    An automated precipitation sampler and an instrumental neutron activation analysis (i.n.a.a.) method for the determination of some major and trace elements in dry atmospheric fall-out and rain-water are presented. The sampler features a rain detector which makes separate collections of dry atmospheric fall-out and rain-water possible. The sampler is equipped with u.v. lamps in order to avoid algal growth during extended collection periods. After collection, the samples are separated into water-soluble and insoluble fractions. The soluble fraction is preconcentrated before analysis by freeze-drying. The i.n.a.a. method involves the measurement of both short- and long-lived radioactivities so that a total of 35 elements can be determined. The possibility of losses during freeze-drying and the accuracy of the i.n.a.a. method were investigated for 7 elements by analysis of a soluble fraction with an independent method, viz. inductively coupled plasma atomic emission spectrometry. (Auth.)

  16. Trace element contents in atmospheric suspended particles: inferences from instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Querol, X.; Alastuey, A.; Lopez-Soler, A.; Boix, A.; Sanfeliu, T.; Martynov, V.V.; Piven, P.I.; Kabina, L.P.; Souschov, P.A.

    1997-01-01

    This study focuses on the determination of trace element concentrations in total suspended particles by instrumental neutron activation analysis (INAA) in two different areas in Northeastern Spain (a rural area influenced by the emissions of a large coal-fired power station, and the urban and industrial areas of Castellon). Total suspended particles were sampled by means of standard MCV high- and medium-volume captors, using cellulose membrane filters of 0.8 and 0.45 μm pore size. Preliminary research was performed on the homogeneous distribution of elements in the sample filters and on the study of blank filters for the calculations of the background average element contents. The results obtained allowed to distinguish different major anthropogenic sources of trace elements in the atmosphere at the sampling sites: (a) Zr, Hf, Sc, U and Th are related to atmospheric pollution derived from the ceramic industry of the Castellon area; (b) As, Cr, Cs, Rb, Sb, Se, Zn are related to traffic and other industrial emission in the Castellon area, and As, Cr, Sb and Zn to power generation emissions in the rural area. (orig.). With 3 figs., 5 tabs

  17. Modeling long-term carbon residue in the ocean-atmosphere system following large CO2 emissions

    Science.gov (United States)

    Towles, N. J.; Olson, P.; Gnanadesikan, A.

    2013-12-01

    We use the LOSCAR carbon cycle model (Zeebe et al., 2009; Zeebe, 2012) to calculate the residual carbon in the ocean and atmosphere following large CO2 emissions. We consider the system response to CO2 emissions ranging from 100 to 20000 PgC, and emission durations from 100 yr to 100 kyr, subject to a wide range of system parameters such as the strengths of silicate weathering and the oceanic biological carbon pump. We define the carbon gain factor as the ratio of residual carbon in the ocean-atmosphere to the total emitted carbon. For moderate sized emissions shorter than about 50 kyr, we find that the carbon gain factor grows during the emission and peaks at about 1.7, primarily due to the erosion of carbonate marine sediments. In contrast, for longer emissions, the carbon gain factor peaks at a smaller value, and for very large emissions (more than 5000 PgC), the gain factor decreases with emission size due to carbonate sediment exhaustion. This gain factor is sensitive to model parameters such as low latitude efficiency of the biological pump. The timescale for removal of the residual carbon (reducing the carbon gain factor to zero) depends strongly on the assumed sensitivity of silicate weathering to atmospheric pCO2, and ranges from less than one million years to several million years.

  18. Observation of the hot GDR in neutron-deficient thorium evaporation residues

    International Nuclear Information System (INIS)

    Seitz, J.P.; Back, B.B.; Carpenter, M.P.; Dioszegi, I.; Eisenman, K.; Heckman, P.; Hofman, D.J.; Kelly, M.P.; Khoo, T.L.; Mitsuoka, S.; Nanal, V.; Pennington, T.; Siemssen, R.H.; Thoennessen, M.; Varner, R.L.

    2005-01-01

    The giant dipole resonance built on excited states was observed in very fissile nuclei in coincidence with evaporation residues. The reaction 48 Ca+ 176 Yb populated evaporation residues of mass A=213-220 with a cross section of ∼200 μb at 259 MeV. The extracted giant dipole resonance parameters are in agreement with theoretical predictions for this mass region

  19. Measurement of residual stress fields in FHPP welding: a comparison between DSPI combined with hole-drilling and neutron diffraction

    Science.gov (United States)

    Viotti, Matias R.; Albertazzi, Armando; Staron, Peter; Pisa, Marcelo

    2013-04-01

    This paper shows a portable device to measure mainly residual stress fields outside the optical bench. This system combines the traditional hole drilling technique with Digital Speckle Pattern Interferometry. The novel feature of this device is the high degree of compaction since only one base supports simultaneously the measurement module and the hole-drilling device. The portable device allows the measurement of non-uniform residual stresses in accordance with the ASTM standard. In oil and gas offshore industries, alternative welding procedures among them, the friction hydro pillar processing (FHPP) is highlighted and nowadays is an important maintenance tool since it has the capability to produce structure repairs without risk of explosions. In this process a hole is drilled and filled with a consumable rod of the same material. The rod, which could be cylindrical or conical, is rotated and pressed against the hole, leading to frictional heating. In order to assess features about the residual stress distribution generated by the weld into the rod as well as into the base material around the rod, welded samples were evaluated by neutron diffraction and by the hole drilling technique having a comparison between them. For the hole drilling technique some layers were removed by using electrical discharge machining (EDM) after diffraction measurements in order to assess the bulk stress distribution. Results have shown a good agreement between techniques.

  20. Neutrons and gamma transport in atmosphere by Tripoli-2 code. Energy deposit and electron current time function

    International Nuclear Information System (INIS)

    Vergnaud, T.; Nimal, J.C.; Ulpat, J.P.; Faucheux, G.

    1988-01-01

    The Tripoli-2 computer code has been adapted to calculate, in addition to energy deposit in matter by neutrons (Kerma) the energy deposit by gamma produced in neutronic impacts and the induced recoil electron current. The energy deposit conduces at air ionization, consequently at a conductibility. This knowledge added at that of electron current permit to resolve the Maxwell equations of electromagnetic field. The study is realized for an atmospheric explosion 100 meters high. The calculations of energy deposit and electron current have been conducted as far as 2.5km [fr

  1. The empirical residual proton-neutron interaction and the onset of collectivity in nuclei

    International Nuclear Information System (INIS)

    Casten, R.F.

    1991-01-01

    The critical role of the residual valence p-n interaction in the development and evolution of collectivity, and the onset of shape/phase transitions, is discussed from the standpoint of phenomenological approaches, and empirical extraction of individual p-n interaction strengths, and simple model calculation of them. 22 refs., 18 figs

  2. Determination of catalyst residues in hydrocarbon fuels by instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Burgess, D.D.

    1982-01-01

    A procedure has been developed for the determination of entrained catalytic cracking catalyst in hydrocarbon fuels. Aluminium is measured by instrumental neutron activation analysis and the amount of catalyst present is calculated from the amount of aluminium found and the known composition of the catalyst. Entrained catalyst may be determined at levels above 3 ppm with a precision of +-2%-25% according to sample composition. Only simple procedures are required. Vanadium may reduce sensitivity by dead time and pulse pile-up. No other interferences were observed. (author)

  3. Instrumental neutron activation analysis of coal and its combustion residues from a power plant

    International Nuclear Information System (INIS)

    Lim, J.M.; Jeong, J.H.; Lee, J.H.

    2013-01-01

    A growing demand of electrical energy derived from coal combustion led to a significant increase of coal ash as residues. Approximately 70 % of the fly ashes are recycled, while most of the bottom ashes have been land-filled in the ash pond in Korea. In this work, to evaluate the potential impacts of the residues from a coal power plant on the environment, its inorganic elemental components were determined by INAA and PGAA. Coal ash samples were collected from the biggest power plant complex in Korea. These samples were analyzed by using the NAA facilities in the HANARO research reactor of the Korea Atomic Energy Research Institute. A total of 31 elements were analyzed in the samples, and certified reference materials were used for the analytical quality control. The enrichment status of a given metal in fuel coal and ashes was investigated by its concentration ratio. In order to assess the impact of the coal combustion residues on ecosystem, their concentrations determined for each respective type of the samples were compared to both reference data and nearby beach sand samples. (author)

  4. Single-Residue Sensitivity in Neutron Reflectivity and Resonant X-ray Reflectivity from Langmuir Monolayers of Synthetic Peptides

    Science.gov (United States)

    Strzalka, Joseph; Satija, Sushil; Dimasi, Elaine; Kuzmenko, Ivan; Gog, Thomas; Blasie, J. Kent

    2004-03-01

    Labeling groups with ^2H to distinguish them in the scattering length density (SLD) profile constitutes the chief advantage of neutron reflectivity (NR) in studying Langmuir monolayers (LM) of lipids and proteins. Solid phase synthesis (SPPS) permits the labeling of a single residue in a peptide. Recent work demonstrates the sensitivity of NR to single ^2H-labeled residues in LM of vectorially oriented α -helical bundle peptides. NR requires comparison of isomorphic samples of all-^1H and ^2H-labeled peptides. Alternately, resonant x-ray reflectivity (RXR) uses only one sample. RXR exploits energy-dependent changes in the scattering factor from heavy atoms to distinguish them within the SLD profile. Peptides may be labeled by SPPS (e.g. Br-Phe), or may have inherent labels (e.g. Fe in heme proteins). As test cases, we studied LM of Br-labeled lipids and peptides with RXR. Both approaches require a model-independent means of obtaining SLD profiles from the reflectivity data. We have applied box-refinement to obtain the gradient SLD profile. This is fit uniquely with a sum of Gaussians and integrated analytically [Blasie et al., PRB 67 224201 (2003)] to provide the SLD profile. Label positions can then be determined to sub-Ångstrom accuracy. This work supported by the NIH (GM55876).

  5. Incorporated residues to sugar cone during the industrial processing evaluated by neutron activation analysis

    International Nuclear Information System (INIS)

    Nadai Fernandes, E.A. de; Bacchi, M.A.

    1990-01-01

    In the Brazilian sugar and alcohol industry a modern agronomic and industrial technology has been developed during the last years, due to the high demand for sugarcane. The intensive harvest mechanization has increased the soil levels in the cane delivered to the mills despite of the introduced washing systems. Electric welding has been used to recuperate the rollers of the mill and other metallic components thus increasing the contents of metals in the processed material. Samples of cane, juice and bagasse were colected at several points of the milling tandem and submitted to neutron activation analysis. The concentrations of Fe, Cr, Co, Zn, Br and Cs showed an increment through the mill, indicating the contribution of the rollers wear. Sc and the rare earth elements La, Ce, Sm and Eu had about the same levels in all samples, therefore they must have come with the soil adhered to the cane. (author)

  6. Residual stress evaluation by neutron diffraction. Some industrial applications and perspectives

    International Nuclear Information System (INIS)

    Rogante, M.

    2001-01-01

    Materials and components of technological and industrial interest can present Residual Stresses (RS), that can be generated during the manufacturing process - e. g. extruding, welding, and forging -, or as a consequence of plastic deformations or thermal treatments. When RS add to external loads, they can enhance fatigue processes, earlier inducing failure of the component. Examples of RS determination in industrial applications are reported: the one focuses on AA 6082 alloy extruded samples, the other on a 2,25Cr1Mo ferritic steel welded pipe after thermal treatment. Other examples are shown, successively, concerning particular industrial problems which need to be studied also by adopting the same technique. (R.P.)

  7. Comparison of Measured Residual Stress in an Extra Thick Multi-pass Weld Using Neutron Diffraction Method and Inherent Strain Method

    International Nuclear Information System (INIS)

    Park, JeongUng; An, GyuBaek; Woo, Wan Chuck

    2015-01-01

    With the increase of large-scale containership, a large amount of high-strength steels with extra thick plates is being extensively used. The welding stress existing in the extra thick welded plates has a significant effect on the integrity of the component in terms of brittle fracture and fatigue behavior. It has been reported that welding residual stress distribution in an extra thick plate can affect the propagation path of the crack. Therefore, it is important to measure the distribution of welding residual stresses for the reliable design of the welded structures. So far various researches have been carried out for the determination of residual stresses on the surface of steels. In this paper, the total residual stresses in the 70 mm thick multipass FACW butt joint were measured by integrating initial stress into ISM. Concretely, two methods named as initial stress integrated ISM and initial inherent strain integrated ISM were employed to determine the total residual stresses. Furthermore, the distributions of residual stresses were compared with the results of the Neutron Diffraction Method(NDM). In order to measure the three dimensional residual stresses in the welded joint with initial stresses existing before welding, initial stress integrated ISM and initial inherent strain integrated ISM were developed. The residual stresses in 70 mm-thick butt joint by flux cored arc welding were carried out with a good accuracy using the two developed methods. The residual stresses in welded joint using both initial stress integrated ISM and initial inherent strain integrated ISM agreed well with the results measured by Neutron Diffraction Method. This suggests that the integrated ISM is a reliable method for residual stress measurement if initial stress existed

  8. Residual stress measurements in a ferritic steel/In625 superalloy dissimilar metal weldment using neutron diffraction and deep-hole drilling

    International Nuclear Information System (INIS)

    Skouras, A.; Paradowska, A.; Peel, M.J.; Flewitt, P.E.J.; Pavier, M.J.

    2013-01-01

    This paper reports the use of non-invasive and semi-invasive techniques to measure the residual stresses in a large dissimilar weldment. This took the form of a butt weld between two sections of a P92 steel pipe, joined using an In625 welding consumable. Residual stress measurements have been carried out on the 30 mm thick welded pipe using the deep-hole drilling technique to characterise the through wall section residual stress distribution for the weld metal, HAZ and parent material. In addition, neutron diffraction measurements have been carried out within the weld zone. Diffraction patterns presented a high intensity and sharp peaks for the base P92 steel material. However measurements in the weld superalloy material were proven problematic as very weak diffraction patterns were observed. A thorough examination of the weld material suggested that the likely cause of this phenomenon was texture in the weld material created during the solidification phase of the welding procedure. This paper discusses the challenges in the execution and interpretation of the neutron diffraction results and demonstrates that realistic measurements of residual stresses can be achieved, in complex dissimilar metal weldments. Highlights: ► One of the few papers to measure residual stresses on dissimilar metal welds. ► Paper managed to provide realistic measurements of residual stresses using the DHD and ND technique. ► Results of this study have demonstrated the effect of texture during the ND measurements.

  9. Weld residual stresses near the bimetallic interface in clad RPV steel: A comparison between deep-hole drilling and neutron diffraction data

    Energy Technology Data Exchange (ETDEWEB)

    James, M.N., E-mail: mjames@plymouth.ac.uk [School of Marine Science and Engineering, University of Plymouth, Drake Circus, Plymouth (United Kingdom); Department of Mechanical Engineering, Nelson Mandela Metropolitan University, Port Elizabeth (South Africa); Newby, M.; Doubell, P. [Eskom Holdings SOC Ltd, Lower Germiston Road, Rosherville, Johannesburg (South Africa); Hattingh, D.G. [Department of Mechanical Engineering, Nelson Mandela Metropolitan University, Port Elizabeth (South Africa); Serasli, K.; Smith, D.J. [Department of Mechanical Engineering, University of Bristol, Queen' s Building, University Walk, Bristol (United Kingdom)

    2014-07-01

    Highlights: • Identification of residual stress trends across bimetallic interface in stainless clad RPV. • Comparison between deep hole drilling (DHD – stress components in two directions) and neutron diffraction (ND – stress components in three directions). • Results indicate that both techniques can assess the trends in residual stress across the interface. • Neutron diffraction gives more detailed information on transient residual stress peaks. - Abstract: The inner surface of ferritic steel reactor pressure vessels (RPV) is clad with strip welded austenitic stainless steel primarily to increase the long-term corrosion resistance of the ferritic vessel. The strip welding process used in the cladding operation induces significant residual stresses in the clad layer and in the RPV steel substrate, arising both from the thermal cycle and from the very different thermal and mechanical properties of the austenitic clad layer and the ferritic RPV steel. This work measures residual stresses using the deep hole drilling (DHD) and neutron diffraction (ND) techniques and compares residual stress data obtained by the two methods in a stainless clad coupon of A533B Class 2 steel. The results give confidence that both techniques are capable of assessing the trends in residual stresses, and their magnitudes. Significant differences are that the ND data shows greater values of the tensile stress peaks (∼100 MPa) than the DHD data but has a higher systematic error associated with it. The stress peaks are sharper with the ND technique and also differ in spatial position by around 1 mm compared with the DHD technique.

  10. Weld residual stresses near the bimetallic interface in clad RPV steel: A comparison between deep-hole drilling and neutron diffraction data

    International Nuclear Information System (INIS)

    James, M.N.; Newby, M.; Doubell, P.; Hattingh, D.G.; Serasli, K.; Smith, D.J.

    2014-01-01

    Highlights: • Identification of residual stress trends across bimetallic interface in stainless clad RPV. • Comparison between deep hole drilling (DHD – stress components in two directions) and neutron diffraction (ND – stress components in three directions). • Results indicate that both techniques can assess the trends in residual stress across the interface. • Neutron diffraction gives more detailed information on transient residual stress peaks. - Abstract: The inner surface of ferritic steel reactor pressure vessels (RPV) is clad with strip welded austenitic stainless steel primarily to increase the long-term corrosion resistance of the ferritic vessel. The strip welding process used in the cladding operation induces significant residual stresses in the clad layer and in the RPV steel substrate, arising both from the thermal cycle and from the very different thermal and mechanical properties of the austenitic clad layer and the ferritic RPV steel. This work measures residual stresses using the deep hole drilling (DHD) and neutron diffraction (ND) techniques and compares residual stress data obtained by the two methods in a stainless clad coupon of A533B Class 2 steel. The results give confidence that both techniques are capable of assessing the trends in residual stresses, and their magnitudes. Significant differences are that the ND data shows greater values of the tensile stress peaks (∼100 MPa) than the DHD data but has a higher systematic error associated with it. The stress peaks are sharper with the ND technique and also differ in spatial position by around 1 mm compared with the DHD technique

  11. Development of a phoswich detector for neutron dose rate measurements in the Earth's atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Doensdorf, Esther Miriam

    2014-04-30

    The Earth is constantly exposed to a stream of energetic particles from outer space. Through the interaction of this radiation with the Earth's magnetosphere and atmosphere a complex radiation field is formed which varies with the location inside the Earth's atmosphere. This radiation field consists of charged and uncharged particles leading to the constant exposure of human beings to radiation. As this ionizing radiation can be harmful for humans, it is necessary to perform dose rate measurements in different altitudes in the Earth's atmosphere. Due to their higher biological effectiveness the exposure to neutrons is more harmful than the exposure to γ-rays and charged particles, which is why the determination of neutron dose rates is the focus of this work. In this work the prototype of a Phoswich detector called PING (Phoswich Instrument for Neutrons and Gammas) is developed to determine dose rates caused by neutrons in the Earth's atmosphere and to distinguish these from γ-rays. The instrument is composed of two different scintillators optically coupled to each other and read out by one common photomultiplier tube. The scintillator package consists of an inner plastic scintillator made of the material BC-412 and a surrounding anti-coincidence made of sodium doped caesium iodide (CsI(Na)). In this work the instrument is calibrated, tested and flown and a procedure for a pulse shape analysis for this instrument is developed. With this analysis it is possible to distinguish pulses from the plastic scintillator and pulses from the CsI(Na). The pulses from the plastic scintillator are mainly due to the interaction of neutrons but there is an energy-dependent contribution of γ-rays to these events. Measurements performed on board an airplane show that the dose rates measured with the developed detector are in the same order of magnitude as results of other instruments. During measurements on board stratospheric balloons the altitude dependence

  12. Investigation of hydrophobic substrates for solution residue analysis utilizing an ambient desorption liquid sampling-atmospheric pressure glow discharge microplasma.

    Science.gov (United States)

    Paing, Htoo W; Marcus, R Kenneth

    2018-03-12

    A practical method for preparation of solution residue samples for analysis utilizing the ambient desorption liquid sampling-atmospheric pressure glow discharge optical emission spectroscopy (AD-LS-APGD-OES) microplasma is described. Initial efforts involving placement of solution aliquots in wells drilled into copper substrates, proved unsuccessful. A design-of-experiment (DOE) approach was carried out to determine influential factors during sample deposition including solution volume, solute concentration, number of droplets deposited, and the solution matrix. These various aspects are manifested in the mass of analyte deposited as well as the size/shape of the product residue. Statistical analysis demonstrated that only those initial attributes were significant factors towards the emission response of the analyte. Various approaches were investigated to better control the location/uniformity of the deposited sample. Three alternative substrates, a glass slide, a poly(tetrafluoro)ethylene (PTFE) sheet, and a polydimethylsiloxane (PDMS)-coated glass slide, were evaluated towards the microplasma analytical performance. Co-deposition with simple organic dyes provided an accurate means of determining the location of the analyte with only minor influence on emission responses. The PDMS-coated glass provided the best performance by virtue of its providing a uniform spatial distribution of the residue material. This uniformity yielded an improved limits of detection by approximately 22× for 20 μL and 4 x for 2 μL over the other two substrates. While they operate by fundamentally different processes, this choice of substrate is not restricted to the LS-APGD, but may also be applicable to other AD methods such as DESI, DART, or LIBS. Further developments will be directed towards a field-deployable ambient desorption OES source for quantitative analysis of microvolume solution residues of nuclear forensics importance.

  13. Non destructive neutron diffraction measurements of cavities, inhomogeneities, and residual strain in bronzes of Ghiberti's relief from the Gates of Paradise

    Science.gov (United States)

    Festa, G.; Senesi, R.; Alessandroni, M.; Andreani, C.; Vitali, G.; Porcinai, S.; Giusti, A. M.; Materna, T.; Paradowska, A. M.

    2011-03-01

    Quantitative neutron studies of cultural heritage objects provide access to microscopic, mesoscopic, and macroscopic structures in a nondestructive manner. In this paper we present a neutron diffraction investigation of a Ghiberti Renaissance gilded bronze relief devoted to the measurement of cavities and inhomogeneities in the bulk of the sample, along with the bulk phase composition and residual strain distribution. The quantitative measurements allowed the determination of the re-melting parts extension, as well as improving current knowledge about the manufacturing process. The study provides significant and unique information to conservators and restorators about the history of the relief.

  14. Non destructive neutron diffraction measurements of cavities, inhomogeneities, and residual strain in bronzes of Ghiberti's relief from the Gates of Paradise

    International Nuclear Information System (INIS)

    Festa, G.; Senesi, R.; Alessandroni, M.; Andreani, C.; Vitali, G.; Porcinai, S.; Giusti, A. M.; Materna, T.; Paradowska, A. M.

    2011-01-01

    Quantitative neutron studies of cultural heritage objects provide access to microscopic, mesoscopic, and macroscopic structures in a nondestructive manner. In this paper we present a neutron diffraction investigation of a Ghiberti Renaissance gilded bronze relief devoted to the measurement of cavities and inhomogeneities in the bulk of the sample, along with the bulk phase composition and residual strain distribution. The quantitative measurements allowed the determination of the re-melting parts extension, as well as improving current knowledge about the manufacturing process. The study provides significant and unique information to conservators and restorators about the history of the relief.

  15. Evaluation between residual stresses obtained by neutron diffraction and simulation for dual phase steel welded by laser process

    Science.gov (United States)

    Kouadri-Henni, Afia; Malard, Benoit

    2018-05-01

    This study aimed at characterizing the residual stresses (RS) distribution of a Dual Phase Steel (DP600) undergoing a Laser Beam Welding (LBW) with two different laser parameters. The RS in the ferritic phase have been experimentally determined by the use of the neutrons diffraction technique. The results confirmed a gradient of RS among different zones both on the top and below surfaces but also through the thickness of the fusion zone. Low compressive stresses were observed in the Base Metal (BM) close to the Heat Affected Zone (HAZ) whereas high tensile stresses were observed in the Fusion Zone (FZ). Numerical results showed a difference in the RS distribution depending on the model used. In the end, it appears that the high temperature gradient, specific to the laser beam, is the main factor governing the RS. Our results suggest as well that the approach regarding the RS should consider not only the temperature but also process parameters. When comparing simulation results with experimental data, the values converge well in some zones, in particular the FZ and the others less.

  16. Residual neutron-induced radionuclides in a soil sample collected in the vicinity of the criticality accident site in Tokai-mura, Japan: A Progress Report

    International Nuclear Information System (INIS)

    Nakanishi, Takashi; Hosotani, Risa; Komura, Kazuhisa; Muroyama, Toshiharu; Kofuji, Hisaki; Murata, Yoshimasa; Kimura, Shinzo; Kumar Sahoo, Sarata; Yonehara, Hidenori; Watanabe, Yoshito; Ban-nai, Tada-aki

    2000-01-01

    Residual neutron-induced radionuclides were measured in a soil sample collected in the vicinity of the location where a criticality accident occurred (in Tokai-mura, from 30 September to 1 October, 1999). Concentrations of 24 Na, 140 La, 122 Sb, 59 Fe, 124 Sb, 46 Sc, 65 Zn, 134 Cs and 60 Co in the soil sample were determined by γ-ray spectrometry, and neutron activation analysis was carried out for selected target elements in the sample. Tentative estimates of the apparent thermal and epithermal neutron fluences which reached the sample were obtained through combined analyses of 59 Fe/ 58 Fe, 124 Sb/ 123 Sb, 46 Sc/ 45 Sc, 65 Zn/ 64 Zn, 134 Cs/ 133 Cs and 60 Co/ 59 Co

  17. Residual stress determination by neutron diffraction in a car gear-shaft made of 20NiCrMo2 alloyed case hardening steel

    Czech Academy of Sciences Publication Activity Database

    Rogante, M.; Mazzanti, M.; Mikula, Pavol; Vrána, Miroslav

    2012-01-01

    Roč. 50, č. 4 (2012), s. 213-220 ISSN 0023-432X R&D Projects: GA ČR(CZ) GAP204/12/1360 Institutional support: RVO:61389005 Keywords : 20NiCrMo2 steel * gear-shaft * caser hardening * residual stress * neutron diffraction Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 0.687, year: 2012

  18. Glyphosate contaminated soil remediation by atmospheric pressure dielectric barrier discharge plasma and its residual toxicity evaluation.

    Science.gov (United States)

    Wang, Tiecheng; Ren, Jingyu; Qu, Guangzhou; Liang, Dongli; Hu, Shibin

    2016-12-15

    Glyphosate was one of the most widely used herbicides in the world. Remediation of glyphosate-contaminated soil was conducted using atmospheric pressure dielectric barrier discharge (DBD) plasma. The feasibility of glyphosate degradation in soil was explored, and the soil leachate toxicity after remediation was assessed via a seed germination test. The experimental results showed that approximately 93.9% of glyphosate was degraded within 45min of DBD plasma treatment with an energy yield of 0.47gkWh -1 , and the degradation process fitted the first-order kinetic model. Increasing the discharge voltage and decreasing the organic matter content of the soil were both found to facilitate glyphosate degradation. There existed appropriate soil moisture to realize high glyphosate degradation efficiency. Glyphosate mineralization was confirmed by changes of total organic carbon (TOC), chemical oxygen demand (COD), PO 4 3- and NO 3 - . The degradation intermediates including glycine, aminomethylphosphonic acid, acetic acid, formic acid, PO 4 3- and NO 3 - , CO 2 and CO were observed. A possible pathway for glyphosate degradation in the soil using this system was proposed. Based on the soil leachate toxicity test using wheat seed germination, the soil did not exhibit any hazardous effects following high-efficiency glyphosate degradation. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Modelling of the long-term fate of pesticide residues in agricultural soils and their surface exchange with the atmosphere: Part II. Projected long-term fate of pesticide residues.

    Science.gov (United States)

    Scholtz, M T; Bidleman, T F

    2007-05-01

    In the first part of this paper, a simple coupled dynamic soil-atmosphere model for studying the gaseous exchange of pesticide soil residues with the atmosphere is described and evaluated by comparing model results with published measurements of pesticide concentrations in air and soil. In Part II, the model is used to study the concentration profiles of pesticide residues in both undisturbed and annually tilled agricultural soils. Future trends are estimated for the measured air and soil concentrations of lindane and six highly persistent pesticides (toxaphene, p,p'-DDE, dieldrin, cis- and trans-chlordane and trans-nonachlor) over a twenty-year period due to volatilization and leaching into the deeper soil. Wet deposition and particle associated pesticide deposition (that increase soil residue concentrations) and soil erosion, degradation in the soil (other than for lindane) and run-off in precipitation are not considered in this study. Estimates of the rain deposition fluxes are reported that show that, other than for lindane, net volatilization fluxes greatly exceed rain deposition fluxes. The model shows that the persistent pesticides studied are highly immobile in soil and that loss of these highly persistent residues from the soil is by volatilization rather than leaching into the deeper soil. The soil residue levels of these six pesticides are currently sources of net volatilization to the atmosphere and will remain so for many years. The maximum rate of volatilization from the soil was simulated by setting the atmospheric background concentration to zero; these simulations show that the rates of volatilization will not be significantly increased since soil resistance rather than the atmospheric concentration controls the volatilization rates. Annual tilling of the soils increases the volatilization loss to the atmosphere. Nonetheless, the model predicts that, if only air-soil exchange is considered, more than 76% of current persistent pesticide residues

  20. Neutron Scattering of Residual Hydrogen in 1,4-Dioxane-D8 Liquid. Understanding Measurements with Molecular Dynamics Simulations

    Energy Technology Data Exchange (ETDEWEB)

    de Almeida, Valmor F. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Liu, Hongjun [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Herwig, Kenneth W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kidder, Michelle [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-01-25

    That incoherent scattering from protiated molecular liquids adds a constant background to the measured scattering intensity is well known, but less appreciated is the fact that coherent scattering is also induced by the presence of hydrogen in a deuterated liquid. In fact, the scattering intensity can be very sensitive, in the small-q region, with respect to the amounts and distribution of residual H in the system. We used 1,4-dioxane liquid to demonstrate that the partial structure factors of the HD and DD atom pairs contribute significantly to inter-molecular scattering and that uncertainty in the extent of deuteration account for discrepancies between simulations and measurements. Both contributions to uncertainty have similar magnitudes: scattering interference of the hydrogen-deuterium pair, and complementary interference from the deuterium-deuterium pair by virtue of chemical inhomogeneity. This situation arises in practice since deuteration of liquids is often 99% or less. A combined experimental and extensive computational study of static thermal neutron scattering of 1,4-dioxane demonstrates the foregoing. We show, through simulations, that the reason for the differences is the content of protiated dioxane (vendors quote 1%). We estimate that up to 5% (at 298K and at 343K) protiated mole fraction may be involved in generating the scattering differences. Finally, we find that the particular distribution of hydrogen in the protiated molecules affects the results significantly; here we considered molecules to be either fully protiated or fully deuterated. This scenario best reconciles the computational and experimental results, and leads us to speculate that the deuteration synthesis process tends to leave a molecule either fully deuterated or fully protiated. Although we have used 1,4-dioxane as a model liquid, the effects described in this study extend to similar liquids and similar systematic experimental/computational studies can be performed to either

  1. Effects of residual hydrogen in sputtering atmosphere on structures and properties of amorphous In-Ga-Zn-O thin films

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Haochun; Ishikawa, Kyohei; Ide, Keisuke [Materials and Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan); Hiramatsu, Hidenori; Hosono, Hideo; Kamiya, Toshio, E-mail: kamiya.t.aa@m.titech.ac.jp [Materials and Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan); Materials Research Center for Element Strategy, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan); Ueda, Shigenori [National Institute for Materials Science, 1-2-1 Sengen, Tsukuba-city, Ibaraki 305-0047 (Japan); Ohashi, Naoki [Materials Research Center for Element Strategy, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan); National Institute for Materials Science, 1-2-1 Sengen, Tsukuba-city, Ibaraki 305-0047 (Japan); Kumomi, Hideya [Materials Research Center for Element Strategy, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan)

    2015-11-28

    We investigated the effects of residual hydrogen in sputtering atmosphere on subgap states and carrier transport in amorphous In-Ga-Zn-O (a-IGZO) using two sputtering systems with different base pressures of ∼10{sup −4} and 10{sup −7 }Pa (standard (STD) and ultrahigh vacuum (UHV) sputtering, respectively), which produce a-IGZO films with impurity hydrogen contents at the orders of 10{sup 20} and 10{sup 19 }cm{sup −3}, respectively. Several subgap states were observed by hard X-ray photoemission spectroscopy, i.e., peak-shape near-valence band maximum (near-VBM) states, shoulder-shape near-VBM states, peak-shape near-conduction band minimum (near-CBM) states, and step-wise near-CBM states. It was confirmed that the formation of these subgap states were affected strongly by the residual hydrogen (possibly H{sub 2}O). The step-wise near-CBM states were observed only in the STD films deposited without O{sub 2} gas flow and attributed to metallic In. Such step-wise near-CBM state was not detected in the other films including the UHV films even deposited without O{sub 2} flow, substantiating that the metallic In is segregated by the strong reduction effect of the hydrogen/H{sub 2}O. Similarly, the density of the near-VBM states was very high for the STD films deposited without O{sub 2}. These films had low film density and are consistent with a model that voids in the amorphous structure form a part of the near-VBM states. On the other hand, the UHV films had high film densities and much less near-VBM states, keeping the possibility that some of the near-VBM states, in particular, of the peak-shape ones, originate from –OH and weakly bonded oxygen. These results indicate that 2% of excess O{sub 2} flow is required for the STD sputtering to compensate the effects of the residual hydrogen/H{sub 2}O. The high-density near-VBM states and the metallic In segregation deteriorated the electron mobility to 0.4 cm{sup 2}/(V s)

  2. Phase space representation of neutron monitor count rate and atmospheric electric field in relation to solar activity in cycles 21 and 22.

    Science.gov (United States)

    Silva, H G; Lopes, I

    Heliospheric modulation of galactic cosmic rays links solar cycle activity with neutron monitor count rate on earth. A less direct relation holds between neutron monitor count rate and atmospheric electric field because different atmospheric processes, including fluctuations in the ionosphere, are involved. Although a full quantitative model is still lacking, this link is supported by solid statistical evidence. Thus, a connection between the solar cycle activity and atmospheric electric field is expected. To gain a deeper insight into these relations, sunspot area (NOAA, USA), neutron monitor count rate (Climax, Colorado, USA), and atmospheric electric field (Lisbon, Portugal) are presented here in a phase space representation. The period considered covers two solar cycles (21, 22) and extends from 1978 to 1990. Two solar maxima were observed in this dataset, one in 1979 and another in 1989, as well as one solar minimum in 1986. Two main observations of the present study were: (1) similar short-term topological features of the phase space representations of the three variables, (2) a long-term phase space radius synchronization between the solar cycle activity, neutron monitor count rate, and potential gradient (confirmed by absolute correlation values above ~0.8). Finally, the methodology proposed here can be used for obtaining the relations between other atmospheric parameters (e.g., solar radiation) and solar cycle activity.

  3. Experimental researches of nuclear reactor neutron and gamma radiation scattering into the atmosphere

    International Nuclear Information System (INIS)

    Istomin, Yu.L.; Zelensky, D.I.; Cherepnin, Yu.S.; Orlov, Yu.V.; Netecha, M.E.; Avaev, V.N.; Vasel'ev, G.A.; Sakamoto, H.; Nomura, Y.; Naito, Y.

    1998-01-01

    In the report there are results of measuring radiation distribution on the caps of the RA and IWG.1M research reactors. Comparative analysis of the results is also in the report. There are neutron spectra in the interval of energies from 10 -9 to 13 MeV above RA and IWG.1M reactors. The spectra were measured with a set of activation detectors. Measurements were calculated to a nominal rate: for RA reactor - 300 kw, for IWG.1M - 7 MW. Thus, in the course of the experiment, vast experimental information relating to distribution of the RA and IWG.1M reactor gamma and neutron radiation scattered in the air for distances varying from 50 to 1000 m from the reactors has become available. The data obtained are to be used to verify the calculation codes and to validate the group nuclear constants

  4. Investigation of the atmospheric particulates deposited on leaves using instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Cercasov, V.

    1985-01-01

    A method for the separation of surface contamination on plant leaves by plastic film stripping was applied. The particulate matter embedded in the film was analysed by neutron activation. The investigation was directed especially towards the determination of the trace element content of the suitable plastic matrices and of the influence of solvents. The practicability of this method is demonstrated by analysing films stripped from plant leaves with different degrees of pollution. (author)

  5. The Catalytic Activity of Modified Zeolite Lanthanum on the Catalytic Cracking of Al-Duara Atmospheric Distillation Residue

    Directory of Open Access Journals (Sweden)

    Karim Khalifa Esgair

    2016-03-01

    Full Text Available Atmospheric residue fluid catalytic cracking was selected as a probe reaction to test the catalytic performance of modified NaY zeolites and prepared NaY zeolites. Modified NaY zeolites have been synthesized by simple ion exchange methods. Three samples of modified zeolite Y have been obtained by replacing the sodium ions in the original sample with lanthanum and the weight percent added are 0.28, 0.53, and 1.02 respectively. The effects of addition of lanthanum to zeolite Y in different weight percent on the cracking catalysts were investigated using an experimental laboratory plant scale of fluidized bed reactor. The experiments have been performed with weight hourly space velocity (WHSV range of 6 to 24 h-1, and the range of temperature from 450 to 510 oC. The activity of the catalyst with 1.02 wt% lanthanum has been shown to be much greater than that of the sample parent NaY. Also it was observed that the addition of the lanthanum causes an increase in the thermal stability of the zeolite.

  6. Mannobiose Binding Induces Changes in Hydrogen Bonding and Protonation States of Acidic Residues in Concanavalin A As Revealed by Neutron Crystallography

    Energy Technology Data Exchange (ETDEWEB)

    Gerlits, Oksana O. [UT/ORNL; Coates, Leighton [Biology; Woods, Robert J. [Complex; Kovalevsky, Andrey [Biology

    2017-08-30

    Plant lectins are carbohydrate-binding proteins with various biomedical applications. Concanavalin A (Con A) holds promise in treating cancerous tumors. To better understand the Con A carbohydrate binding specificity, we obtained a room-temperature neutron structure of this legume lectin in complex with a disaccharide Manα1–2Man, mannobiose. The neutron structure afforded direct visualization of the hydrogen bonding between the protein and ligand, showing that the ligand is able to alter both protonation states and interactions for residues located close to and distant from the binding site. An unprecedented low-barrier hydrogen bond was observed forming between the carboxylic side chains of Asp28 and Glu8, with the D atom positioned equidistant from the oxygen atoms having an O···D···O angle of 101.5°.

  7. Assessment of Atmospheric heavy metal deposition in North Egypt aerosols using neutron activation analysis and optical emission inductively coupled plasma

    International Nuclear Information System (INIS)

    El-Araby, E.H.; Abd El-Wahab, M.; Diab, H.M.; El-Desouky, T.M.; Mohsen, M.

    2011-01-01

    The aim of the present study is to assess the current level of atmospheric heavy metal pollution of aerosols in different cities of North Egypt using the neutron activation analysis and optical emission inductively coupled plasma techniques. The results revealed that the highest concentrations of particulate matter PM 10 and total suspended particulate matter were close to industrial areas. From the results of the enrichment factor calculations, the most significant elements of anthropogenic origin are Ba, Sb, Ce and Zn. - Highlights: → Average concentration of Cd using OE-ICP is below detection limit for all the samples. → Maximum average concentration of Pb in PM10 and TSP is 5425 and 570.3, respectively. → Concentration of 20 elements in PM 10 and TSP aerosols are determined using the NAA. → EF revealed that Pb, Ba, Br, Ce, Hf, La Sb and Zn are of anthropogenic origin.

  8. Atmospheric deposition of heavy metals in Serbia studied by moss biomonitoring, neutron activation analysis and GIS technology

    International Nuclear Information System (INIS)

    Frontas'eva, M.V.; Galinskaya, T.E.; Pavlov, S.S.; Kumar, M.; Matavuly, M.; Radnovic, D.; Steinnes, E.

    2002-01-01

    The results of a pilot study on atmospheric deposition of heavy metals and other trace elements using the moss biomonitoring technique in the northern part of Serbia and some areas of Bosnia are presented. Samples of Hypnum cupressiforme along with some other moss types were collected at 92 sites during the summer of 2000. A total of 44 elements were determined by instrumental neutron activation analysis using epithermal neutrons. The observed levels of Cu, Zn, As, Ag, Cd, In, Sb, etc. in the area surrounding the town of Bor (Serbia) are comparable to those reported from similar industrial areas in other countries such as the Copper Basin in Poland and the South Urals of Russia. In the same region the maximum Se and Mo concentrations are the highest ever recorded in biomonitoring studies using mosses. High median concentrations of Fe and Ni in Serbian mosses are associated with a crustal component as apparent from factor analysis of the moss data. This component could be a result of windblown soil dust (most of the samples were taken from agricultural regions) or deposition of ash from coal-burning power stations. Some specific elements such as Cl and V may originate from known industrial sources, but at certain places high values in the moss samples are suspected to be associated with fires in oil refineries damaged during the 1999 NATO military action

  9. Atmospheric Deposition of Heavy Metals in Serbia Studied by Moss Biomonitoring, Neutron Activation Analysis and GIS Technology

    CERN Document Server

    Frontasyeva, M V; Kumar, M; Matavuly, M; Pavlov, S S; Radnovic, D; Steinnes, E

    2002-01-01

    The results of a pilot study on atmospheric deposition of heavy metals and other trace elements using the moss biomonitoring technique in the northern part of Serbia and some areas of Bosnia are presented. Samples of Hypnum cupressiforme along with some other moss types were collected at 92 sites during the summer of 2000. A total of 44 elements were determined by instrumental neutron activation analysis using epithermal neutrons. The observed levels of Cu, Zn, As, Ag, Cd, In, Sb, etc. in the area surrounding the town of Bor (Serbia) are comparable to those reported from similar industrial areas in other countries such as the Copper Basin in Poland and the South Urals of Russia. In the same region the maximum Se and Mo concentrations are the highest ever recorded in biomonitoring studies using mosses. High median concentrations of Fe and Ni in Serbian mosses are associated with a crustal component as apparent from factor analysis of the moss data. This component could be a result of windblown soil dust (most ...

  10. Residual stress state in an induction hardened steel bar determined by synchrotron- and neutron diffraction compared to results from lab-XRD

    International Nuclear Information System (INIS)

    Holmberg, Jonas; Steuwer, Axel; Stormvinter, Albin; Kristoffersen, Hans; Haakanen, Merja; Berglund, Johan

    2016-01-01

    Induction hardening is a relatively rapid heat treatment method to increase mechanical properties of steel components. However, results from FE-simulation of the induction hardening process show that a tensile stress peak will build up in the transition zone in order to balance the high compressive stresses close to the surface. This tensile stress peak is located in the transition zone between the hardened zone and the core material. The main objective with this investigation has been to non-destructively validate the residual stress state throughout an induction hardened component. Thereby, allowing to experimentally confirming the existence and magnitude of the tensile stress peak arising from rapid heat treatment. For this purpose a cylindrical steel bar of grade C45 was induction hardened and characterised regarding the microstructure, hardness, hardening depth and residual stresses. This investigation shows that a combined measurement with synchrotron/neutron diffraction is well suited to non-destructively measure the strains through the steel bar of a diameter of 20 mm and thereby making it possible to calculate the residual stress profile. The result verified the high compressive stresses at the surface which rapidly changes to tensile stresses in the transition zone resulting in a large tensile stress peak. Measured stresses by conventional lab-XRD showed however that at depths below 1.5 mm the stresses were lower compared to the synchrotron and neutron data. This is believed to be an effect of stress relaxation from the layer removal. The FE-simulation predicts the depth of the tensile stress peak well but exaggerates the magnitude compared to the measured results by synchrotron/neutron measurements. This is an important knowledge when designing the component and the heat treatment process since this tensile stress peak will have great impact on the mechanical properties of the final component.

  11. Residual stress state in an induction hardened steel bar determined by synchrotron- and neutron diffraction compared to results from lab-XRD

    Energy Technology Data Exchange (ETDEWEB)

    Holmberg, Jonas, E-mail: jonas.holmberg@swerea.se [Swerea IVF AB, Argongatan 30, 431 22 Mölndal (Sweden); University West, 461 86 Trollhättan (Sweden); Steuwer, Axel [Nelson Mandela Metropolitan University, Gardham Avenue, 6031 Port Elizabeth (South Africa); Stormvinter, Albin; Kristoffersen, Hans [Swerea IVF AB, Argongatan 30, 431 22 Mölndal (Sweden); Haakanen, Merja [Stresstech OY, Tikkutehtaantie 1, 40 800 Vaajakoski (Finland); Berglund, Johan [Swerea IVF AB, Argongatan 30, 431 22 Mölndal (Sweden)

    2016-06-14

    Induction hardening is a relatively rapid heat treatment method to increase mechanical properties of steel components. However, results from FE-simulation of the induction hardening process show that a tensile stress peak will build up in the transition zone in order to balance the high compressive stresses close to the surface. This tensile stress peak is located in the transition zone between the hardened zone and the core material. The main objective with this investigation has been to non-destructively validate the residual stress state throughout an induction hardened component. Thereby, allowing to experimentally confirming the existence and magnitude of the tensile stress peak arising from rapid heat treatment. For this purpose a cylindrical steel bar of grade C45 was induction hardened and characterised regarding the microstructure, hardness, hardening depth and residual stresses. This investigation shows that a combined measurement with synchrotron/neutron diffraction is well suited to non-destructively measure the strains through the steel bar of a diameter of 20 mm and thereby making it possible to calculate the residual stress profile. The result verified the high compressive stresses at the surface which rapidly changes to tensile stresses in the transition zone resulting in a large tensile stress peak. Measured stresses by conventional lab-XRD showed however that at depths below 1.5 mm the stresses were lower compared to the synchrotron and neutron data. This is believed to be an effect of stress relaxation from the layer removal. The FE-simulation predicts the depth of the tensile stress peak well but exaggerates the magnitude compared to the measured results by synchrotron/neutron measurements. This is an important knowledge when designing the component and the heat treatment process since this tensile stress peak will have great impact on the mechanical properties of the final component.

  12. Neutron activation analysis on sediments from Victoria Land, Antarctica. Multi-elemental characterization of potential atmospheric dust sources

    International Nuclear Information System (INIS)

    Baccolo, G.; Maggi, V.; Baroni, C.; Clemenza, M.; Motta, A.; Nastasi, M.; Previtali, E.; University of Milano-Bicocca, Milan; Delmonte, B.; Salvatore, M.C.

    2014-01-01

    The elemental composition of 40 samples of mineral sediments collected in Victoria Land, Antarctica, in correspondence of ice-free sites, is presented. Concentration of 36 elements was determined by instrumental neutron activation analysis, INAA. The selection of 6 standard reference materials and the development of a specific analytical procedure allowed to reduce measurements uncertainties and to verify the reproducibility of the results. The decision to analyze sediment samples from Victoria Land ice-free areas is related to recent investigations regarding mineral dust content in the TALos Dome ICE core (159deg11'E; 72deg49'S, East Antarctica, Victoria Land), in which a coarse local fraction of dust was recognized. The characterization of Antarctic potential source areas of atmospheric mineral dust is the first step to identify the active sources of dust for the Talos Dome area and to reconstruct the atmospheric pathways followed by air masses in this region during different climatic periods. Principal components analysis was used to identify elements and samples correlations; attention was paid specially to rare earth elements (REE) and incompatible/compatible elements (ICE) in respect to iron, which proved to be the most discriminating elemental groups. The analysis of REE and ICE concentration profiles supported evidences of chemical weathering in ice-free areas of Victoria Land, whereas cold and dry climate conditions of the Talos Dome area and in general of East Antarctica. (author)

  13. Monitoring the heavy metal atmospheric deposition in Romania using the neutron activation analysis of bio-indicators

    International Nuclear Information System (INIS)

    Lucaciu, Adriana

    1997-01-01

    This research is the direct result of a protocol between NIPNE-HH Bucharest, Romania and JINR-Dubna, Russia on one side, and NIPNE-HH Bucharest, Romania and the University of Trondheim, Norway on the other side. Since the summer of 1995, a systematic sampling of bio-indicators has been carried out. The bio-indicators are represented by three species of bryophytes with an endemic development in the Romanian area: Hylocomium splendens, Hypnum cupresiforme and Pleurozium schreberi. A large area of 45,000 km 2 , including the Carpathian Arch between the Olt River Gorge (Southern Carpathian Mountains) and the northern Romanian border (Eastern Carpathian Mountains) was covered. Some of the samples were prepared in the laboratory and analyzed by nuclear analysis methods of a high sensitivity and accuracy i.e., neutron activation analysis and atomic absorption spectrometry. Other samples are to be prepared and analyzed. The results will be shown as distribution maps for heavy metal concentrations in the studied area. The analysis were carried out at NIPNE-HH-Bucharest, JINR-Dubna and Trondheim University. Part of the results have already been included in the European Atlas of the Heavy Metal Atmospheric Depositions, published by the Northern Countries Council. The distribution maps of atmospheric depositions in Romania will also be included in the above mentioned Atlas. (author)

  14. Study of the long-range transport of atmospheric pollutants by instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Jin Yangshao

    1994-01-01

    Aerosol samples were collected to study the characteristics of marine aerosols in the different western Pacific ocean areas. During the first cruise from 15 October to 25 November 1989, aerosol samples were collected with a kA-200 Andersen cascade impactor and a kB-120 sampler. Instrumental neutron activation analysis was used to determine the elemental composition of the aerosols. The concentrations of crustal and pollution elements in aerosols were higher over the ocean area close to the China coast and decreased very rapidly with increasing distance from land. The morphology and elemental composition of aerosol particles showed that the seasalt particles may conglomerate with small crustal and pollution particles from land to form large particles. (author). 4 refs, 1 fig., 1 tab

  15. Stress-free reference for neutron diffraction measurement of residual stress in butt-welded joints of austenitic stainless steel pipes

    International Nuclear Information System (INIS)

    Maekawa, Akira; Takahashi, Tsuneo; Tsuji, Takashi; Suzuki, Hiroshi; Moriai, Atsushi

    2012-01-01

    Stress-free lattice spacing d_0 has the most influence on reliability of neutron stress measurements made using an angle dispersive method. However, it is hard to evaluate the lattice spacing of welded structures and ductile materials such as stainless steel accurately. In this study, suitable measurement conditions for d_0 of welded pipe joints of austenitic stainless steel were discussed. The d_0 values derived from {311} and {111} reflections, which are often used in austenitic stainless steel for residual stress measurement, were examined. Comparison of the residual strains and stresses evaluated using the obtained d_0 and the finite element analysis showed that the way the d_0 values were chosen affected the measurement accuracy significantly. The stress measurement accuracy was remarkably improved when the {311} reflection was used and the proper d_0 value was chosen in the respective neutron diffraction measurements. For instance, for the axial diffraction measurements using the {311} reflection, it was recommended that only the axial d_0 value of the {311} reflection be used; the measurements using the {111} reflection were less accurate due to the large Young's modulus. Additionally, a lower diffraction angle was judged to be one of the factors leading to a decrease of the strain measurement accuracy. (author)

  16. Cooldown to residual heat removal entry conditions using atmospheric dump valves and auxiliary pressurizer spray following a loss-of-offsite power at Calvert Cliffs, Unit 1

    International Nuclear Information System (INIS)

    Jenks, R.P.

    1984-01-01

    An investigation of cooldown using atmospheric dump valves (ADVs) and auxiliary pressurizer spray (APS) following loss-of-offsite power at Calvert Cliffs-1 showed residual heat removal entry conditions could not be reached with the plant ADVs alone. Use of APS with the plant ADVs enhanced depressurization, but still provided insufficient cooldown. Effective cooldown and depressurization was shown to occur when rated steady state flow through the ADVs was increased by a factor of four. 6 refs., 30 figs., 2 tabs

  17. Unexpected alignment patterns in high-j intruder bands evidence for a strong residual neutron proton interaction?

    International Nuclear Information System (INIS)

    Wyss, R.; Johnson, A.; Royal Inst. of Tech., Stockholm

    1990-01-01

    The alignment of h 11/12 protons in νi 13/2 intruder bands in mass A = 130 region is investigated. The lack of a clear h 11/12 band crossing is compared with the alignment pattern of i 13/2 neutrons in πi 13/2 intruder bands in mass A = 180 region. The very smooth rise in angular momentum in the intruder bands is related to a possible neutron proton interaction between the single intruder orbital and the aligned two-quasiparticle configuration. 36 refs., 3 figs

  18. Neutron activation analysis of lichens for atmospheric pollution study in Sao Paulo city

    International Nuclear Information System (INIS)

    Fuga, Alessandra; Saiki, Mitiko; Marcelli, Marcelo P.

    2005-01-01

    In the present study instrumental neutron activation analysis has been applied to determine the elements accumulated in samples of Canoparmelia texana, a specie of lichen, collected in regions with different levels of pollution: Intervales State Park, an area considered non polluted that belongs to Atlantic Forest ecosystem and distinct sites in the metropolitan region of Sao Paulo city. The results obtained in the analysis showed that samples collected in the clean area indicated lower concentrations of elements than those obtained for samples from metropolitan region. The concentrations of the elements Ba, Ca, Cl, Fe, K, Mn, Na, Rb and Zn were obtained at μg g -1 levels and the elements As, Br, Co, Cr, Cs, La, Sb, Sc, Se and U at ng g -1 levels. Cluster analysis was applied to classify into distinct groups the sites using the element concentrations in these samples. The accuracy and precision of the results were evaluated by IAEA 336 Lichen reference material analysis and the data given for this material were in agreement with certified values with relative standard deviations lower than 11,4%. (author)

  19. Evaluation on double-wall-tube residual stress distribution of sodium-heated steam generator by neutron diffraction and numerical analysis

    International Nuclear Information System (INIS)

    Kisohara, N.; Suzuki, H.; Akita, K.; Kasahara, N.

    2012-01-01

    A double-wall-tube is nominated for the steam generator heat transfer tube of future sodium fast reactors (SFRs) in Japan, to decrease the possibility of sodium/water reaction. The double-wall-tube consists of an inner tube and an outer tube, and they are mechanically contacted to keep the heat transfer of the interface between the inner and outer tubes by their residual stress. During long term SG operation, the contact stress at the interface gradually falls down due to stress relaxation. This phenomenon might increase the thermal resistance of the interface and degrade the tube heat transfer performance. The contact stress relaxation can be predicted by numerical analysis, and the analysis requires the data of the initial residual stress distributions in the tubes. However, unclear initial residual stress distributions prevent precious relaxation evaluation. In order to resolve this issue, a neutron diffraction method was employed to reveal the tri-axial (radius, hoop and longitudinal) initial residual stress distributions in the double-wall-tube. Strain gauges also were used to evaluate the contact stress. The measurement results were analyzed using a JAEA's structural computer code to determine the initial residual stress distributions. Based on the stress distributions, the structural computer code has predicted the transition of the relaxation and the decrease of the contact stress. The radial and longitudinal temperature distributions in the tubes were input to the structural analysis model. Since the radial thermal expansion difference between the inner (colder) and outer (hotter) tube reduces the contact stress and the tube inside steam pressure contributes to increasing it, the analytical model also took these effects into consideration. It has been conduced that the inner and outer tubes are contacted with sufficient stresses during the plant life time, and that effective heat transfer degradation dose not occur in the double-wall-tube SG. (authors)

  20. Development of nondestructive hybrid measuring method for three-dimensional residual stress distribution of thick welded joint. Hybrid measuring method of inherent strain method and neutron diffraction method

    International Nuclear Information System (INIS)

    Nakacho, Keiji; Kasahara, Norifumi; Tamura, Ryota

    2012-01-01

    The measuring methods of the residual stress are classified into destructive one and nondestructive one. The inherent strain method (ISM) is destructive one. The neutron diffraction method (NDM) is nondestructive one. But the measurable depth is limited within about 20 mm and the method cannot measure the weld zone, without destruction of the object. So, in this study, the hybrid measuring method has been developed, by combining the ISM and the NDM. The theory of the hybrid method is the same as the ISM. In the analysis, the strains measured by the NDM without destruction are used. This hybrid measuring method is a true nondestructive measuring method for a thick welded joint. The applicability of the hybrid method has been verified by simulation, using a butt welded joint of thick pipes. In the simulation, the reliable order of the strains measured by the present NDM is very important, and was considered as 10 micro. The measurable regions by the present NDM were assumed. Under the above conditions, the data (the residual elastic strains assumed to be measured by the NDM) were made, and used in the ISM. As a result of such simulation, it has been cleared that the estimated residual stress has very high accuracy, if enough data are used. The required number of data is less than the ISM. (author)

  1. Study of occupational health impact of atmospheric pollution on exposed workers at an iron and steel complex by using neutron activation analysis of scalp hair

    International Nuclear Information System (INIS)

    Chai, Z.F.; Qian, Q.F.; Feng, X.Q.; Zhang, P.Q.; Liu, N.Q.; Feng, W.Y.

    2004-01-01

    The occupational health impact of atmospheric pollution on exposed workers at one iron and steel complex was studied by instrumental neutron activation analysis of workers' hair samples and medical examination. The experimental results indicate that there is a positive correlation between the high inhalation amounts of iron and other trace elements by the exposed workers and the symptom of their high blood pressure and hypoglycemia, which implies that the atmospheric environment polluted by iron and steel industry has an adverse health impact on the exposed workers. The measures to relieve and abate the occupational diseases caused by air-borne particulate matter should be taken. (author)

  2. The determination of pesticide residues and contaminants in vegetables by means of neutron activation analysis. Part of a coordinated programme on nuclear detection and analysis

    International Nuclear Information System (INIS)

    Mongkolphanta, S.

    1977-11-01

    Neutron activation techniques have been applied to study the existence of pesticide residues (As, Br, Hg) and pollutants (Cd, Co, Zn) in local vegetable and fruit samples, polished and unpolished glutinous and non-glutinous milled rice, and fish caught in polluted and unpolluted areas of the Gulf of Thailand. Since the baseline levels of these toxic elements in vegetables, fruits, rice and fish are not known as yet, the results cannot be regarded as conclusive. Furthermore, no significant difference was observed in the concentration of these elements in fish caught in polluted and unpolluted areas. The Gulf of Thailand does not therefore appear to be polluted at present. The substoichiometric isotope dilution technique was successfully applied to mercury determinations, and only to a limited extent to Cd due to shutdown of the TRR-1 reactor

  3. Neutron diffraction measurements for the determination of heat treatment effectiveness in generating compressive residual stress in an automotive crown gear

    International Nuclear Information System (INIS)

    Albertini, G.; Fiori, F.; Girardin, E.; Giuliani, A.; Pyzalla, A.; Quadrini, E.

    1999-01-01

    Complete text of publication follows. Thermal austenitizing and tempering treatments are being developed in automotive industry to prevent crack initiation and avoid crack propagation, especially in components where stress intensity factors influence the stress field and then the fatigue life of the component itself. This is the case of crown gears, where the teeth root undergoes frequently to cracking when tensile residual stresses are present at the surface, as typical loads are impulsive and very high. The sign reversal of these stresses is the aim of austenitizing and tempering treatments. In this work residual stress measurements carried out at HMI-BENSC are presented, in a UNI55Cr3 steel crown gear submitted to such kind of treatments, performed with a new multi-frequency induction technique whose effectiveness is checked. (author)

  4. The high pressure liquid chromatography and its application to the separation of polynuclear aromatic hydrocarbons in atmospheric dust and burning residues

    International Nuclear Information System (INIS)

    Lopez, M.-C.

    1975-09-01

    A new technique of analysis is described: the high speed liquid chromatography or more exactly the high performance liquid chromatography because of the progress achieved on the new packings of the columns. The main types of chromatography, according to the phenomena involved are described: adsorption, partition, ion-exchange and exclusion chromatography. A brief outline is given of the theory for determination of stationary and mobile phases in order to obtain the optimum conditions of separation. Some exemples of possible applications are given, particularly the use of this technique for the separation of polycyclic aromatic hydrocarbons in atmospheric pollution and burning residues [fr

  5. Measurement of the Residual Gases O2 and CO2 in Meat Products Packed in Modified Atmosphere

    Directory of Open Access Journals (Sweden)

    Jozef Čapla

    2013-02-01

    Full Text Available Nowadays, consumers have increased demand for quality and food safety and also rising demand for natural foods without chemical additives. There are many ways to presserve freshness of these products, one of them is modified atmosphere packaging, which can mean elimination and/or replacement surrounding the product before closing it in package with a mixture of gases other than the original ambient air atmosphere. for replacement of atmosphere are generally used three types of gases such as carbon dioxide, oxygen and nitrogen. this type of packaging is often used for meat and meat products, which belongs to foods that are under normal conditions perishable and for increasing the shelf life of meat products are also used various other preservation methods or their combinations. Packaging of meat and meat products in modified atmosphere is usually made with a high content of carbon dioxide, which has good bacteriostatic and fungistatic effect and is also an effective mean for increasing the shelf life of packaged products during storage and sale.

  6. The Optical/UV Excess of X-Ray-dim Isolated Neutron Stars. I. Bremsstrahlung Emission from a Strangeon Star Atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Weiyang; Lu, Jiguang; Men, Yunpeng; Xu, Renxin [School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); Tong, Hao [Xinjiang Astronomical Observatory, Chinese Academy of Sciences, Urumqi 830011 (China); Ge, Mingyu [Key Laboratory for Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Li, Zhaosheng, E-mail: r.x.xu@pku.edu.cn [Department of Physics, Xiangtan University, Xiangtan 411105 (China)

    2017-03-01

    X-ray-dim isolated neutron stars (XDINSs) are characterized by Planckian spectra in X-ray bands, but show optical/ultraviolet (UV) excesses: the factors by which the measured photometry exceeds those extrapolated from X-ray spectra. To solve this problem, a radiative model of bremsstrahlung emission from a plasma atmosphere is established in the regime of a strangeon star. A strangeon star atmosphere could simply be regarded as the upper layer of a normal neutron star. This plasma atmosphere, formed and maintained by the interstellar-medium-accreted matter due to the so-called strangeness barrier, is supposed to be of two temperatures. All seven XDINS spectra could be well fitted by the radiative model, from optical/UV to X-ray bands. The fitted radiation radii of XDINSs are from 7 to 13 km, while the modeled electron temperatures are between 50 and 250 eV, except RX J0806.4–4123, with a radiation radius of ∼3.5 km, indicating that this source could be a low-mass strangeon star candidate. This strangeon star model could further be tested by soft X-ray polarimetry, such as the Lightweight Asymmetry and Magnetism Probe, which is expected to be operational on China’s space station around 2020.

  7. Evaporation residue cross sections and average neutron multiplicities in the /sup 64/Ni+/sup 92/Zr and /sup 12/C+/sup 144/Sm reactions leading to /sup 156/Er

    Energy Technology Data Exchange (ETDEWEB)

    Janssens, R.V.F.; Holzmann, R.; Henning, W.; Khoo, T.L.; Lesko, K.T.; Stephans, G.S.F.; Radford, D.C.; Van den Berg, A.M.; Kuehn, W.; Ronningen, R.M.

    1986-11-27

    Evaporation residue cross sections and neutron multiplicity distributions have been measured for the /sup 12/C+/sup 144/Sm and /sup 64/Ni+/sup 92/Zr reactions leading to the same compound nucleous /sup 156/Er. Statistical model calculations can account for the data in the /sup 12/C-induced reaction. In contrast, the inhibition of neutron emission with respect to statistical model predictions seen in /sup 64/Ni+/sup 92/Zr cannot be explained even with the inclusion of the broad angular momentum distributions required to describe the fusion cross section data.

  8. Report on the workshop on neutrons for engineering and its conclusions regarding the residual-stress diffractometer at the Australian Replacement Research Reactor

    International Nuclear Information System (INIS)

    2002-01-01

    The purpose of the workshop was to: inform the Australian research organizations and universities of the capabilities of an engineering and materials science instrument; promote the use of neutron diffraction to map and investigate strains/stresses in materials and components for industrial applications and research; identify the future needs and opportunities in this area; present the options for a stress mapping diffractometer at the Replacement Research Reactor and receive feedback on these options; identify the ancillary equipment and facilities required. Presented papers and discussions at the workshop indicated that there are a number of important benefits to Australia in the building of a first-class instrument for materials science and engineering and many residual stress-related problems in a wide variety of fields in Australia, such as the manufacturing industries, mining, oil and gas, rail transport, defense and life extension. Stress scanning provides another tool for solving problems to complement facilities at the major research institutes, CSIRO, AMIRA, DSTO, ANSTO and the universities. It will create a regional pool of experts who may tap into the pool of expertise internationally. The turn around time for tests for Australian customers will be reduced thus avoiding having to go overseas to have the tests performed. From an educational perspective the instrument will build expertise in Australia and will help to attract graduates into engineering. A detailed list of the attendees and affiliations is in Appendix C

  9. Determination of elements in the atmosphere of Valle de Toluca by Neutron Activation (July 1992 - April 1993)

    International Nuclear Information System (INIS)

    Garcia S, I.

    1994-01-01

    The purpose of this study is to continue with the environmental monitoring program of Valle de Toluca by means of the Neutron Activation Analysis and atomic absorption techniques. The analytical results corresponding to the period of July 1992 to April 1993, and the analyzed elements by Neutron Activation were Na, V, Br, Al and Mn, while Cr and Pb were analyzed by Atomic Absorption Spectroscopy. Since the study is a joint project with the Facultad de Quimica de la Universidad Autonoma del Estado de Mexico, the purpose is to continue with this type of chemical analysis. (Author)

  10. Solid residues

    International Nuclear Information System (INIS)

    Mulder, E.; Duin, P.J. van; Grootenboer, G.J.

    1995-01-01

    A summary is presented of the many investigations that have been done on solid residues of atmospheric fluid bed combustion (AFBC). These residues are bed ash, cyclone ash and bag filter ash. Physical and chemical properties are discussed and then the various uses of residues (in fillers, bricks, gravel, and for recovery of aluminium) are summarised. Toxicological properties of fly ash and stack ash are discussed as are risks of pneumoconiosis for workers handling fly ash, and contamination of water by ashes. On the basis of present information it is concluded that risks to public health from exposure to emissions of coal fly ash from AFBC appear small or negligible as are health risk to workers in the coal fly ash processing industry. 35 refs., 5 figs., 12 tabs

  11. Study of atmospheric aerosols in Zaire by instrumental neutron activation analysis, atomic absorption spectrophotometry and ion-exchange chromatography

    International Nuclear Information System (INIS)

    Tshiashala, M.D.; Lumu, B.M.; Matamba, K.; Ronneau, C.

    1992-01-01

    Instrumental neutron activation analysis and atomic absorption spectroscopy were applied to the determination of trace element abundances in airborne particulate matter collected throughout Kinshasa, Zaire. Statistical treatment of the resulting data was used to assess the variations between sites and to identify the sources of the pollutants. 10 refs, 5 tabs

  12. An improved crude oil atmospheric distillation process for energy integration: Part II: New approach for energy saving by use of residual heat

    International Nuclear Information System (INIS)

    Benali, Tahar; Tondeur, Daniel; Jaubert, Jean Noël

    2012-01-01

    In Part I of this paper, it was shown on thermodynamic grounds that introducing a flash in the preheating train of an atmospheric oil distillation process, together with an appropriate introduction of the resulting vapour into the column, could potentially bring substantial energy savings, by reducing the duty of the preheating furnace, by doing some pre-fractionation and by reducing the column irreversibilities. Part II expands on this idea by showing how this can be done while keeping the throughput and the product characteristics unchanged. The outcome is that placing several flashes after the heat exchangers and feeding the corresponding vapour streams to the appropriate trays of the column reduces the pumparound flows and the heat brought to the preheating train. The resulting heat deficit may then be compensated in an additional heat exchanger by using low level heat recuperated from the products of the distillation and/or imported from other processes. The use of this residual heat reduces the furnace duty by approximately an equivalent amount. Thus high level energy (fuel-gas burnt in the furnace) is replaced by residual low level heat. The simulation with an example flowsheet shows that the savings on fuel could be as high as 21%. - Highlights: ► Flash installation in the preheating train of the crude oil distillation process. ► Pumparound streams and heat sent to the preheating train are reduced. ► A high level heat deficit is induced and replaced by low level heat. ► Considerable energy savings and greenhouse gas emissions are achieved.

  13. A new method based on low background instrumental neutron activation analysis for major, trace and ultra-trace element determination in atmospheric mineral dust from polar ice cores

    Energy Technology Data Exchange (ETDEWEB)

    Baccolo, Giovanni, E-mail: giovanni.baccolo@mib.infn.it [Graduate School in Polar Sciences, University of Siena, Via Laterina 8, 53100, Siena (Italy); Department of Environmental Sciences, University of Milano-Bicocca, P.zza della Scienza 1, 20126, Milano (Italy); INFN, Section of Milano-Bicocca, P.zza della Scienza 3, 20126, Milano (Italy); Clemenza, Massimiliano [INFN, Section of Milano-Bicocca, P.zza della Scienza 3, 20126, Milano (Italy); Department of Physics, University of Milano-Bicocca, P.zza della Scienza 3, 20126, Milano (Italy); Delmonte, Barbara [Department of Environmental Sciences, University of Milano-Bicocca, P.zza della Scienza 1, 20126, Milano (Italy); Maffezzoli, Niccolò [Centre for Ice and Climate, Niels Bohr Institute, Juliane Maries Vej, 30, 2100, Copenhagen (Denmark); Nastasi, Massimiliano; Previtali, Ezio [INFN, Section of Milano-Bicocca, P.zza della Scienza 3, 20126, Milano (Italy); Department of Physics, University of Milano-Bicocca, P.zza della Scienza 3, 20126, Milano (Italy); Prata, Michele; Salvini, Andrea [LENA, University of Pavia, Pavia (Italy); Maggi, Valter [Department of Environmental Sciences, University of Milano-Bicocca, P.zza della Scienza 1, 20126, Milano (Italy); INFN, Section of Milano-Bicocca, P.zza della Scienza 3, 20126, Milano (Italy)

    2016-05-30

    Dust found in polar ice core samples present extremely low concentrations, in addition the availability of such samples is usually strictly limited. For these reasons the chemical and physical analysis of polar ice cores is an analytical challenge. In this work a new method based on low background instrumental neutron activation analysis (LB-INAA) for the multi-elemental characterization of the insoluble fraction of dust from polar ice cores is presented. Thanks to an accurate selection of the most proper materials and procedures it was possible to reach unprecedented analytical performances, suitable for ice core analyses. The method was applied to Antarctic ice core samples. Five samples of atmospheric dust (μg size) from ice sections of the Antarctic Talos Dome ice core were prepared and analyzed. A set of 37 elements was quantified, spanning from all the major elements (Na, Mg, Al, Si, K, Ca, Ti, Mn and Fe) to trace ones, including 10 (La, Ce, Nd, Sm, Eu, Tb, Ho, Tm, Yb and Lu) of the 14 natural occurring lanthanides. The detection limits are in the range of 10{sup −13}–10{sup −6} g, improving previous results of 1–3 orders of magnitude depending on the element; uncertainties lies between 4% and 60%. - Highlights: • A new method based on neutron activation for the multi-elemental characterization of atmospheric dust entrapped in polar ice cores is proposed. • 37 elements were quantified in μg size dust samples with detection limits ranging from 10{sup −13} to 10{sup −6} g. • A low background approach and a clean analytical protocol improved INAA performances to unprecedented levels for multi-elemental analyses.

  14. The use of neutron diffraction for the determination of the in-depth residual stresses profile in weld coatings; A utilizacao da difracao de neutroes na determinacao do perfil de tensoes residuais em revestimentos por soldadura

    Energy Technology Data Exchange (ETDEWEB)

    Marques, Maria Jose; Batista, A.C.; Nobre, J.P. [Universidade de Coimbra (Portugal). Dept. de Fisica. Centro de Estudos de Materiais por Difraccao de Raios X (CEMDRX); Loureiro, Altino [Universidade de Coimbra (Portugal). Dept. de Engenharia Mecanica. Centro de Engenharia Mecanica (CEMUC); Kornmeier, Joana R., E-mail: mjvaz@fe.up.pt [Technische Universitaet Muenchen, Garching (Germany). FRM II

    2013-04-15

    The neutron diffraction is a non-destructive technique, particularly suitable for the analysis of residual stress fields in welds. The technique is used in this article to study ferritic samples, coated by submerged arc welding using stainless steel filler metals. This procedure is often used for manufacturing process equipment for chemical and nuclear industries, for ease of implementation and economic reasons. The main disadvantage of that processes is the cracking phenomenon that often occurs at the interface between the base material and coatings, which can be minimized by performing post-weld stress relief heat treatments. The samples analyzed in this study were made of carbon steel plates, coated by submerged arc welding two types of stainless steel filler metals. For the first layer was used one EN 12 072 - S 2 U 23 12 electrode, while for the second and third layers were used an EN 12 072 - 19 12 3 S L electrode. After cladding, the samples were submitted to a post-weld heat treatment for 1 hour at 620 deg C. The residual stress profiles obtained by neutron diffraction evidence the relaxation of residual stress given by the heat treatment. (author)

  15. Disruptive tension under normalized atmospheric pulse and residual tension on lightning arresters power systems: statistical methods application. Practical results and comments; Ensaios de tensao disruptiva sob impulso atmosferico normalizado e tensao residual em para-raios para sistemas de potencia: a aplicacao de metodos estatisticos. Comentarios e resultados praticos

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, M.L.B. [ELETRONORTE, Brasilia (Brazil); Oliveira, A.L. [Eletricidade da Sao Paulo S.A. (ELETROPAULO), Sao Paulo, SP (Brazil)

    1991-12-31

    The necessity of complementary assays of disruptive tension under normalized atmospheric pulses and residual tension on lightning arresters, as well as the adequate use of a statistical treatment of its results are commented. Some statistical methods and its applicability on lightning arresters characteristics surveys, and its quality control are proposed 8 refs., 5 figs., 3 tabs.

  16. Atmospheric depositions of rare earth elements in Albania studied by the moss biomonitoring technique, neutron activation analysis and GIS technology

    International Nuclear Information System (INIS)

    Allajbeu, Sh.; Lazo, P.; Yushin, N.S.; Frontasyeva, M.V.; Qarri, F.; Duliu, O.G.

    2015-01-01

    Rare earth elements (REE) are conservative elements, scarcely derived from anthropogenic sources. The mobilization of REE in the environment requires their monitoring in environmental matrices, where they are mainly present at trace levels. The results on determination of the content of 11 elements by epithermal neutron activation analysis (ENAA) at the IBR-2 reactor in Dubna in carpet-forming moss species Hypnum cupressiforme collected from 44 sampling sites over the whole Albanian territory are presented and discussed. The paper is focused on Sc and lanthanides, as well as Fe and Th, the last ones showing correlations with the investigated REE. With the exception of Fe, all other elements were never determined in the air deposition of Albania. The STATISTICA"T"M 10 software was used for data analysis. The median values for the content of elements under investigation were compared to those in Bulgaria, Macedonia, Romania and Serbia, as well as Norway selected as a pristine area. Therefore, it was shown that the accumulation of REE in mosses is associated with the wind blown metal-enriched soils that are pointed out as the main emitting factor. [ru

  17. s-process studies in the light of new experimental cross sections: Distribution of neutron fluences and r-process residuals

    International Nuclear Information System (INIS)

    Kaeppeler, F.; Beer, H.; Wisshak, K.; Clayton, D.D.; Macklin, R.L.; Ward, R.A.

    1981-08-01

    A best set of neutron-capture cross sections has been evaluated for the most important s-process isotopes. With this data base, s-process studies have been carried out using the traditional model which assumes a steady neutron flux and an exponential distribution of neutron irradiations. The calculated sigmaN-curve is in excellent agreement with the empirical sigmaN-values of pure s-process nuclei. Simultaneously, good agreement is found between the difference of solar and s-process abundances and the abundances of pure r-process nuclei. We also discuss the abundance pattern of the iron group elements where our s-process results complement the abundances obtained from explosive nuclear burning. The results obtained from the traditional s-process model such as seed abundances, mean neutron irradiations, or neutron densities are compared to recent stellar model calculations which assume the He-burning shells of red giant stars as the site for the s-process. (orig.) [de

  18. Characterization of bauxite residue (red mud) for 235U, 238U, 232Th and 40K using neutron activation analysis and the radiation dose levels as modeled by MCNP.

    Science.gov (United States)

    Landsberger, S; Sharp, A; Wang, S; Pontikes, Y; Tkaczyk, A H

    2017-07-01

    This study employs thermal and epithermal neutron activation analysis (NAA) to quantitatively and specifically determine absorption dose rates to various body parts from uranium, thorium and potassium. Specifically, a case study of bauxite residue (red mud) from an industrial facility was used to demonstrate the feasibility of the NAA approach for radiological safety assessment, using small sample sizes to ascertain the activities of 235 U, 238 U, 232 Th and 40 K. This proof-of-concept was shown to produce reliable results and a similar approach could be used for quantitative assessment of other samples with possible radiological significance. 238 U and 232 Th were determined by epithermal and thermal neutron activation analysis, respectively. 235 U was determined based on the known isotopic ratio of 238 U/ 235 U. 40 K was also determined using epithermal neutron activation analysis to measure total potassium content and then subtracting its isotopic contribution. Furthermore, the work demonstrates the application of Monte Carlo Neutral-Particle (MCNP) simulations to estimate the radiation dose from large quantities of red mud, to assure the safety of humans and the surrounding environment. Phantoms were employed to observe the dose distribution throughout the human body demonstrating radiation effects on each individual organ. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Assessment of atmospheric deposition of heavy metals and other elements in Belgrade using the moss biomonitoring technique and neutron activation analysis.

    Science.gov (United States)

    Anicić, Mira; Frontasyeva, Marina V; Tomasević, Milica; Popović, Aleksandar

    2007-06-01

    This study aimed at assessing atmospheric deposition of heavy metals and other elements using the moss genera Brachythecium sp. (B. rutabulum and B. salebrosum) and Eurhynchium sp. (E. hians and E. striatum) collected in autumn 2004 in the urban area of Belgrade. The concentrations of 36 elements (Na, Mg, Al, Cl, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Zn, As, Se, Br, Rb, Sr, Mo, Sb, I, Cs, Ba, La, Ce, Sm, Tb, Dy, Hf, Ta, W, Hg, Th, U) were determined in moss and local topsoil samples by instrumental neutron activation analysis. The concentration of elements in moss positively correlated to those obtained for topsoil. High enrichment factors for As, Zn, Mo, Br, Sb, Se, Hg and Cl, calculated to continental crust composition, gave an evidence for anthropogenic impact on urban area, mainly due to intensive vehicular traffic and fossil fuel combustion. The concentration of elements in moss, characteristic for fossil fuel combustion, obtained in this study were substantially lower than in the previous investigation (2000) conducted in the area of Belgrade. The level of concentrations for V, Cr, Ni, and As in moss from this study correlated to those measured for neighboring countries, and were several times higher than the base-level data from low polluted areas. The level of accumulated elements in both investigated moss genera were similar and all studied species could be combined for biomonitoring purposes in urban areas.

  20. PRELIMINARY RESULTS OF ATMOSPHERIC DEPOSITION OF MAJOR AND TRACE ELEMENTS IN THE GREATER AND LESSER CAUCASUS MOUNTAINS STUDIED BY THE MOSS TECHNIQUE AND NEUTRON ACTIVATION ANALYSIS

    Directory of Open Access Journals (Sweden)

    S. Shetekauri

    2015-05-01

    Full Text Available The method of moss biomonitoring of atmospheric deposition of trace elements was applied for the first time in the western Caucasus Mountains to assess the environmental situation in this region. The sixteen moss samples have been collected in 2014 summer growth period along altitudinal gradients in the range of altitudes from 600 m to 2665 m. Concentrations of Na, Mg, Al, Cl, K, Ca, Ti, V, Mn, Fe, Zn, As, Br, Rb, Mo, Cd, I, Sb, Ba, La, Sm, W, Au, and U determined by neutron activation analysis in the moss samples are reported. A comparison with the data for moss collected in Norway (pristine area was carried out.  Multivariate statistical analysis of the results was used for assessment pollution sources in the studied part of the Caucasus. The increase in concentrations of most of elements with rising altitude due to gradually disappearing vegetation cover and wind erosion of soil was observed. A comparison with the available data for moss collected in the Alps at the same altitude (~ 2500 m was performed.

  1. Assessment of atmospheric deposition of heavy metals and other elements in Belgrade using the moss biomonitoring technique and neutron activation analysis

    International Nuclear Information System (INIS)

    Anicic, M.; Tomasevic, M.; Frontas'eva, M.V.; Popovic, A.

    2006-01-01

    The study aimed at assessing atmospheric deposition of heavy metals and other elements using the moss genera Brachythecium sp. (B. rutabulum and B. salebrosum) and Eurhynchium sp. (E. hians and E. striatum) collected in autumn 2004 in the urban area of Belgrade. The concentrations of 36 elements (Na, Mg, Al, Cl, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Zn, As, Se, Br, Rb, Sr, Mo, Sb, I, Cs, Ba, La, Ce, Sm, Tb, Dy, Hf, Ta, W, Hg, Th, U) were determined in moss and local topsoil samples by instrumental neutron activation analysis. The concentration of elements in moss positively correlated to those obtained for topsoil. High enrichment factors for As, Zn, Mo, Br, Sb, Se, Hg, and Cl, calculated to continental crust composition, gave an evidence for anthropogenic impact on urban area, mainly due to intensive vehicular traffic and fossil fuel combustion. The concentrations of elements in moss, characteristic for fossil fuel combustion, obtained in this study, were substantially lower than in the previous investigation (2000) conducted in the area of Belgrade. The level of concentrations for V, Cr, Ni, and As in moss from this study correlated to those measured for neighboring countries, and were several times higher than the base-level data from low polluted areas. The level of accumulated elements in both investigated moss genera were similar and all studied species could be combined for biomonitoring purposes in urban areas

  2. A time series approach to the correction for atmosphere effects and the significance of a semi-diurnal variation in corrected intensities of secondary cosmic ray neutrons and mesons (NM64 and MT64)

    International Nuclear Information System (INIS)

    Huijsmans, D.P.

    1982-01-01

    The aim of this research was to distinguish as accurately as possible between two mechanisms behind a half-daily variation in detected numbers of neutrons and mesons in the secondary cosmic ray particles at sea level. These two mechanisms are due to air pressure variations at sea level and affect the number of primary particles with a certain arrival direction. The distribution among arrival directions in the ecliptic plane varies if a gradient exists in the guiding centre density of primaries in directions perpendicular to the neutral sheet. Chapter 2 is devoted to the calculation of a physically and statistically justifiable determination of the barometric coefficient for neutron measurements and air pressures. Chapter 3 deals with the estimation of atmospheric correction coefficients for the elimination of the influence of changing atmospheric conditions on the number of detected mesons. For mesons the variation of total mass, and also the variations in mass-distribution along the trajectory of the mesons are important. After correction for atmospheric variations using the resulting atmospheric correction coefficients from chapter 2 and 3, the influence of the structure of the interplanetary magnetic field near the earth is examined in chapter 4. 0inally, in chapter 5, a power spectral analysis of variations in corrected intensities of neutrons and mesons is carried out. Such an analysis distinguishes the variance of a time series into contributions within small frequency intervals. From the power spectra of variations on a yearly basis, a statistically fundamented judgement can be given as to the significance of the semi-diurnal variation during the different phases of the solar magnetic activity cycle. (Auth.)

  3. Residual-stress measurements

    Energy Technology Data Exchange (ETDEWEB)

    Ezeilo, A N; Webster, G A [Imperial College, London (United Kingdom); Webster, P J [Salford Univ. (United Kingdom)

    1997-04-01

    Because neutrons can penetrate distances of up to 50 mm in most engineering materials, this makes them unique for establishing residual-stress distributions non-destructively. D1A is particularly suited for through-surface measurements as it does not suffer from instrumental surface aberrations commonly found on multidetector instruments, while D20 is best for fast internal-strain scanning. Two examples for residual-stress measurements in a shot-peened material, and in a weld are presented to demonstrate the attractive features of both instruments. (author).

  4. Evaluation of residual stresses in composite materials by using neutron diffraction; study of elasto-plasticity; Etude des composites a matrice metallique par la technique de la diffraction de neutrons: analyse du comportement elastoplastique et evaluation des contraintes residuelles

    Energy Technology Data Exchange (ETDEWEB)

    Levy-Tubiana, R

    1999-11-05

    This work deals with the study of Metal Matrix Composites (MMC) using neutrons diffraction method and the analysis of the elastoplastic behavior in such materials. First, we evaluated macro-stresses in aluminium MMC reinforced with 17%vol. of SiC particles. One of the analyzed sample has been 4 point bending deformed, measurements have been performed after relaxation. The difference between the coefficients of thermal expansion constrains the matrix to be in tensile state and the particles in compressive state in the sample which has not be deformed. In the sample deformed, the MMC response is predicted by the science of Resistance Materials applied to a bent bar. We assume that macro-stresses are the sum of stresses with different origins (elastic, plastic, thermal mismatch): elastic mismatch is evaluated by Eshelby model and we determined micro-stresses in the unbent bar: they are equivalent and constant along width direction. For the bent bar, we observe relaxation of thermal stresses in the surface region. Theses results are confirmed by measurements of tensile/compressive sample using neutrons diffraction method. We also observed the influence of mechanical and thermal treatment on such MMC: the shear stress (established by the auto-coherent model) depends only on the way of cooling. Finally, a study was performed on titanium MMC for SNECMA on rotor beings used in the gas turbine engine industry. Evolution of stresses between felloe and boring is confirmed by a finite elements modeling and they are the first experimental results in this application. (author)

  5. Polarized neutrons

    International Nuclear Information System (INIS)

    Williams, W.G.

    1988-01-01

    The book on 'polarized neutrons' is intended to inform researchers in condensed matter physics and chemistry of the diversity of scientific problems that can be investigated using polarized neutron beams. The contents include chapters on:- neutron polarizers and instrumentation, polarized neutron scattering, neutron polarization analysis experiments and precessing neutron polarization. (U.K.)

  6. Neutron--neutron logging

    International Nuclear Information System (INIS)

    Allen, L.S.

    1977-01-01

    A borehole logging tool includes a steady-state source of fast neutrons, two epithermal neutron detectors, and two thermal neutron detectors. A count rate meter is connected to each neutron detector. A first ratio detector provides an indication of the porosity of the formation surrounding the borehole by determining the ratio of the outputs of the two count rate meters connected to the two epithermal neutron detectors. A second ratio detector provides an indication of both porosity and macroscopic absorption cross section of the formation surrounding the borehole by determining the ratio of the outputs of the two count rate meters connected to the two thermal neutron detectors. By comparing the signals of the two ratio detectors, oil bearing zones and salt water bearing zones within the formation being logged can be distinguished and the amount of oil saturation can be determined. 6 claims, 2 figures

  7. Neutrons and Nuclear Engineering

    International Nuclear Information System (INIS)

    Ekkebus, Allen E.

    2007-01-01

    Oak Ridge National Laboratory hosted two workshops in April 2007 relevant to nuclear engineering education. In the Neutron Stress, Texture, and Phase Transformation for Industry workshop (http://neutrons.ornl.gov/workshops/nst2/), several invited speakers gave examples of neutron stress mapping for nuclear engineering applications. These included John Root of National Research Council of Canada, Mike Fitzpatrick of the UK's Open University, and Yan Gao of GE Global Research on their experiences with industrial and academic uses of neutron diffraction. Xun-Li Wang and Camden Hubbard described the new instruments at ORNL that can be used for such studies. This was preceded by the Neutrons for Materials Science and Engineering educational symposium (http://neutrons.ornl.gov/workshops/edsym2007). It was directed to the broad materials science and engineering community based in universities, industry and laboratories who wish to learn what the neutron sources in the US can provide for enhancing the understanding of materials behavior, processing and joining. Of particular interest was the presentation of Donald Brown of Los Alamos about using 'Neutron diffraction measurements of strain and texture to study mechanical behavior of structural materials.' At both workshops, the ORNL neutron scattering instruments relevant to nuclear engineering studies were described. The Neutron Residual Stress Mapping Facility (NRSF2) is currently in operation at the High Flux Isotope Reactor; the VULCAN Engineering Materials Diffractometer will begin commissioning in 2008 at the Spallation Neutron Source. For characteristics of these instruments, as well as details of other workshops, meetings, capabilities, and research proposal submissions, please visit http://neutrons.ornl.gov. To submit user proposals for time on NRSF2 contact Hubbard at hubbardcratornl.gov

  8. Neutron Research in HANARO

    International Nuclear Information System (INIS)

    Kim, Hark Rho

    2005-01-01

    HANARO (High-flux Advanced Neutron Application Reactor), which was designed and constructed by indigenous technology, is a world-class multi-purpose research reactor with a design thermal power of 30 MW, providing high neutron flux for various applications in Korea. HANARO has been operated since its first criticality in February 1995, and is now successfully utilized in such areas as neutron beam research, fuel and materials tests, radioisotopes and radiopharmaceuticals production, neutron activation analysis, and neutron transmutation doping, etc. A number of experimental facilities have been developed and installed since the beginning of reactor operation, and R and D activities for installing more facilities are actively under progress. Three flux traps in the core (CT, IR1, IR2), providing a high fast neutron flux, can be used for materials and fuel irradiation tests. They are also proper for production of high specific activity radioisotopes. Four vertical holes in the outer core region, abundant in epithermal neutrons, are used for fuel or material tests and radioisotope production. In the heavy water reflector region, 25 vertical holes with high quality thermal neutrons are located for radioisotope production, neutron activation analysis, neutron transmutation doping and cold neutron source installation. The two largest holes named NTD1 and NTD2 are for neutron transmutation doping, CNS for the cold neutron source installation, and LH for the irradiation of large targets. The high resolution powder diffractometer (HRPD) became operational in 1998, followed by the four circle diffractometer (FCD) in 1999, the residual stress instrument (RSI) in 2000, and the small angle neutron spectrometer (SANS) in 2001, respectively. HRPD and SANS became the most popular instruments these days, attracting wide range of users from academia, institutes and industries. We have made a lot of efforts during the last 10 years to develop some key components such as

  9. The stability of CaS in circulating fluidized bed boiler residue and the possible release of H2S gas to the atmosphere

    International Nuclear Information System (INIS)

    Mattisson, T.; Lyngfelt, A.

    1995-01-01

    During the combustion of coal, SO 2 is released to the atmosphere. Because of environmental concerns with acid rain, the capture of SO 2 is an important issue. In fluidized bed combustion SO 2 is captured in-situ by limestone or dolomite to form CaSO 4 . This product is stable and can be disposed of or reused as gypsum. In order to capture the sulphur as CaSO 4 oxidizing conditions are necessary. In a fluidized bed boiler (FBB) CaS may form in regions with reducing conditions, and FBB ashes sampled under irregular operating conditions may contain as much as 50 % of the captured sulphur as CaS. The stability of CaS in a landfill environment is thus very important. It is possible that the sulphide decomposes in the presence of moisture or runoff leachate with the subsequent release of H 2 S gas. This re-release of captured sulphur could have a substantial effect on the overall sulphur capture efficiency, with more sulphur released to the atmosphere than previously thought. In this study the stability of CaS in bed ashes from a 12 MW circulating FBB combusting coal has been investigated, with focus on the release of H 2 S gas. (orig.)

  10. Handling of Solid Residues

    International Nuclear Information System (INIS)

    Medina Bermudez, Clara Ines

    1999-01-01

    The topic of solid residues is specifically of great interest and concern for the authorities, institutions and community that identify in them a true threat against the human health and the atmosphere in the related with the aesthetic deterioration of the urban centers and of the natural landscape; in the proliferation of vectorial transmitters of illnesses and the effect on the biodiversity. Inside the wide spectrum of topics that they keep relationship with the environmental protection, the inadequate handling of solid residues and residues dangerous squatter an important line in the definition of political and practical environmentally sustainable. The industrial development and the population's growth have originated a continuous increase in the production of solid residues; of equal it forms, their composition day after day is more heterogeneous. The base for the good handling includes the appropriate intervention of the different stages of an integral administration of residues, which include the separation in the source, the gathering, the handling, the use, treatment, final disposition and the institutional organization of the administration. The topic of the dangerous residues generates more expectation. These residues understand from those of pathogen type that are generated in the establishments of health that of hospital attention, until those of combustible, inflammable type, explosive, radio-active, volatile, corrosive, reagent or toxic, associated to numerous industrial processes, common in our countries in development

  11. Ultracold neutrons

    International Nuclear Information System (INIS)

    Steenstrup, S.

    Briefly surveys recent developments in research work with ultracold neutrons (neutrons of very low velocity, up to 10 m/s at up to 10 -7 eV and 10 -3 K). Slow neutrons can be detected in an ionisation chamber filled with B 10 F 3 . Very slow neutrons can be used for investigations into the dipole moment of neutrons. Neutrons of large wave length have properties similar to those of light. The limit angle for total reflection is governed by the wave length and by the material. Total reflection can be used to filter ultracold neutrons out of the moderator material of a reactor. Total reflection can also be used to store ultracold neutrons but certain problems with storage have not yet been clarified. Slow neutrons can be made to lose speed in a neutron turbine, and come out as ultracold neutrons. A beam of ultracold neutrons could be used in a neutron microscope. (J.S.)

  12. Commercial applications of neutron scattering

    International Nuclear Information System (INIS)

    Hutchings, M.T.

    1993-01-01

    The fact that industry is now willing to pay the full commercial cost for certain neutron scattering experiments aimed at solving its urgent materials - related problems is a true testimony to the usefulness of neutrons as microscopic probes. This paper gives examples of such use of three techniques drawn mainly from our experience at AEA Technology Harwell Laboratory. These are diffraction to measure residual stress, small angle neutron scattering to examine hardening precipitates in ferritic steels brought about by irradiation, and reflectivity to study amorphous diamond layers deposited on silicon. In most cases it is the penetrative power of the neutron which proves to be its best asset for commercial industrial applicaitons. (author)

  13. On-line solid phase extraction-liquid chromatography-tandem mass spectrometry for insect repellent residue analysis in surface waters using atmospheric pressure photoionization.

    Science.gov (United States)

    Molins-Delgado, Daniel; García-Sillero, Daniel; Díaz-Cruz, M Silvia; Barceló, Damià

    2018-04-06

    Insect repellents (IRs) are a group of organic chemicals whose function is to prevent the ability of insects of landing in a surface. These compounds have been found in the environment and may pose a risk to non-target organisms. In this study, an on-line solid phase extraction - high performance liquid chromatography-tandem mass spectrometry multiresidue method was developed using an atmospheric photoionization source (SPE-HPLC-(APPI)-MS/MS). The use of the APPI as an alternative ionization technique to electrospray (ESI) and atmospheric pressure chemical ionization (APCI) allowed expanding the range of analytical techniques suitable for the analysis of IRs, so far relied in gas chromatography. High sensitivity and precision was reached with method limits of quantification between 0.2 and 4.6 ng l -1 and interday and intraday precision equal or below 15%. The validated method was applied to the study of surface water samples from three European river basins with different flow regime (Adige River in Italy, Sava River in the Balkans, and Evrotas River in Greece). The results showed that two IRs (DEET and Bayrepel) were ubiquitous in the Sava and Evrotas basins, reaching concentrations as high as 105 μg l -1 of Bayrepel in the Sava River, and 5 μg l -1 of DEET in the Evrotas River. Densely populated areas and effluent waste waters are pointed out as the responsible for this pollution. In the alpine river Adige, only three samples showed low levels of IRs (6.01-37.8 ng l -1 ). The concentrations measured were used to perform an environmental risk assessment based on the hazard quotients (HQs) estimation approach by using the chronic and acute eco-toxicity data available. The results revealed that despite the high frequency and eventually high concentrations of these IRs determined in the three basins, only few sites were at risk, with 1 < HQs < 3.3. Copyright © 2018 The Author(s). Published by Elsevier B.V. All rights reserved.

  14. Observation of Neutron Skyshine from an Accelerator Based Neutron Source

    Energy Technology Data Exchange (ETDEWEB)

    Franklyn, C. B. [Radiation Science Department, Necsa, PO Box 582, Pretoria 0001 (South Africa)

    2011-12-13

    A key feature of neutron based interrogation systems is the need for adequate provision of shielding around the facility. Accelerator facilities adapted for fast neutron generation are not necessarily suitably equipped to ensure complete containment of the vast quantity of neutrons generated, typically >10{sup 11} n{center_dot}s{sup -1}. Simulating the neutron leakage from a facility is not a simple exercise since the energy and directional distribution can only be approximated. Although adequate horizontal, planar shielding provision is made for a neutron generator facility, it is sometimes the case that vertical shielding is minimized, due to structural and economic constraints. It is further justified by assuming the atmosphere above a facility functions as an adequate radiation shield. It has become apparent that multiple neutron scattering within the atmosphere can result in a measurable dose of neutrons reaching ground level some distance from a facility, an effect commonly known as skyshine. This paper describes a neutron detection system developed to monitor neutrons detected several hundred metres from a neutron source due to the effect of skyshine.

  15. Characterization of Hospital Residuals

    International Nuclear Information System (INIS)

    Blanco Meza, A.; Bonilla Jimenez, S.

    1997-01-01

    The main objective of this investigation is the characterization of the solid residuals. A description of the handling of the liquid and gassy waste generated in hospitals is also given, identifying the source where they originate. To achieve the proposed objective the work was divided in three stages: The first one was the planning and the coordination with each hospital center, in this way, to determine the schedule of gathering of the waste can be possible. In the second stage a fieldwork was made; it consisted in gathering the quantitative and qualitative information of the general state of the handling of residuals. In the third and last stage, the information previously obtained was organized to express the results as the production rate per day by bed, generation of solid residuals for sampled services, type of solid residuals and density of the same ones. With the obtained results, approaches are settled down to either determine design parameters for final disposition whether for incineration, trituration, sanitary filler or recycling of some materials, and storage politics of the solid residuals that allow to determine the gathering frequency. The study concludes that it is necessary to improve the conditions of the residuals handling in some aspects, to provide the cleaning personnel of the equipment for gathering disposition and of security, minimum to carry out this work efficiently, and to maintain a control of all the dangerous waste, like sharp or polluted materials. In this way, an appreciable reduction is guaranteed in the impact on the atmosphere. (Author) [es

  16. Residual stresses

    International Nuclear Information System (INIS)

    Sahotra, I.M.

    2006-01-01

    The principal effect of unloading a material strained into the plastic range is to create a permanent set (plastic deformation), which if restricted somehow, gives rise to a system of self-balancing within the same member or reaction balanced by other members of the structure., known as residual stresses. These stresses stay there as locked-in stresses, in the body or a part of it in the absence of any external loading. Residual stresses are induced during hot-rolling and welding differential cooling, cold-forming and extruding: cold straightening and spot heating, fabrication and forced fitting of components constraining the structure to a particular geometry. The areas which cool more quickly develop residual compressive stresses, while the slower cooling areas develop residual tensile stresses, and a self-balancing or reaction balanced system of residual stresses is formed. The phenomenon of residual stresses is the most challenging in its application in surface modification techniques determining endurance mechanism against fracture and fatigue failures. This paper discusses the mechanism of residual stresses, that how the residual stresses are fanned and what their behavior is under the action of external forces. Such as in the case of a circular bar under limit torque, rectangular beam under limt moment, reclaiming of shafts welds and peening etc. (author)

  17. Residual stresses

    International Nuclear Information System (INIS)

    Macherauch, E.

    1978-01-01

    Residual stresses are stresses which exist in a material without the influence of external powers and moments. They come into existence when the volume of a material constantly changes its form as a consequence of mechanical, thermal, and/or chemical processes and is hindered by neighbouring volumes. Bodies with residual stress are in mechanical balance. These residual stresses can be manifested by means of all mechanical interventions disturbing this balance. Acoustical, optical, radiological, and magnetical methods involving material changes caused by residual stress can also serve for determining residual stress. Residual stresses have an ambivalent character. In technical practice, they are feared and liked at the same time. They cause trouble because they can be the cause for unexpected behaviour of construction elements. They are feared since they can cause failure, in the worst case with catastrophical consequences. They are appreciated, on the other hand, because, in many cases, they can contribute to improvements of the material behaviour under certain circumstances. But they are especially liked for their giving convenient and (this is most important) mostly uncontrollable explanations. For only in very few cases we have enough knowledge and possibilities for the objective evaluation of residual stresses. (orig.) [de

  18. The Los Alamos Neutron Science Center Spallation Neutron Sources

    International Nuclear Information System (INIS)

    Nowicki, Suzanne F.; Wender, Stephen A.; Mocko, Michael

    2017-01-01

    The Los Alamos Neutron Science Center (LANSCE) provides the scientific community with intense sources of neutrons, which can be used to perform experiments supporting civilian and national security research. These measurements include nuclear physics experiments for the defense program, basic science, and the radiation effect programs. This paper focuses on the radiation effects program, which involves mostly accelerated testing of semiconductor parts. When cosmic rays strike the earth's atmosphere, they cause nuclear reactions with elements in the air and produce a wide range of energetic particles. Because neutrons are uncharged, they can reach aircraft altitudes and sea level. These neutrons are thought to be the most important threat to semiconductor devices and integrated circuits. The best way to determine the failure rate due to these neutrons is to measure the failure rate in a neutron source that has the same spectrum as those produced by cosmic rays. Los Alamos has a high-energy and a low-energy neutron source for semiconductor testing. Both are driven by the 800-MeV proton beam from the LANSCE accelerator. The high-energy neutron source at the Weapons Neutron Research (WNR) facility uses a bare target that is designed to produce fast neutrons with energies from 100 keV to almost 800 MeV. The measured neutron energy distribution from WNR is very similar to that of the cosmic-ray-induced neutrons in the atmosphere. However, the flux provided at the WNR facility is typically 5×107 times more intense than the flux of the cosmic-ray-induced neutrons. This intense neutron flux allows testing at greatly accelerated rates. An irradiation test of less than an hour is equivalent to many years of neutron exposure due to cosmic-ray neutrons. The low-energy neutron source is located at the Lujan Neutron Scattering Center. It is based on a moderated source that provides useful neutrons from subthermal energies to ~100 keV. The characteristics of these sources

  19. The Los Alamos Neutron Science Center Spallation Neutron Sources

    Science.gov (United States)

    Nowicki, Suzanne F.; Wender, Stephen A.; Mocko, Michael

    The Los Alamos Neutron Science Center (LANSCE) provides the scientific community with intense sources of neutrons, which can be used to perform experiments supporting civilian and national security research. These measurements include nuclear physics experiments for the defense program, basic science, and the radiation effect programs. This paper focuses on the radiation effects program, which involves mostly accelerated testing of semiconductor parts. When cosmic rays strike the earth's atmosphere, they cause nuclear reactions with elements in the air and produce a wide range of energetic particles. Because neutrons are uncharged, they can reach aircraft altitudes and sea level. These neutrons are thought to be the most important threat to semiconductor devices and integrated circuits. The best way to determine the failure rate due to these neutrons is to measure the failure rate in a neutron source that has the same spectrum as those produced by cosmic rays. Los Alamos has a high-energy and a low-energy neutron source for semiconductor testing. Both are driven by the 800-MeV proton beam from the LANSCE accelerator. The high-energy neutron source at the Weapons Neutron Research (WNR) facility uses a bare target that is designed to produce fast neutrons with energies from 100 keV to almost 800 MeV. The measured neutron energy distribution from WNR is very similar to that of the cosmic-ray-induced neutrons in the atmosphere. However, the flux provided at the WNR facility is typically 5×107 times more intense than the flux of the cosmic-ray-induced neutrons. This intense neutron flux allows testing at greatly accelerated rates. An irradiation test of less than an hour is equivalent to many years of neutron exposure due to cosmic-ray neutrons. The low-energy neutron source is located at the Lujan Neutron Scattering Center. It is based on a moderated source that provides useful neutrons from subthermal energies to ∼100 keV. The characteristics of these sources, and

  20. Neutron-absorbing alloys

    International Nuclear Information System (INIS)

    Portnoi, K.I.; Arabei, L.B.; Gryaznov, G.M.; Levi, L.I.; Lunin, G.L.; Kozhukhov, V.M.; Markov, J.M.; Fedotov, M.E.

    1975-01-01

    A process is described for the production of an alloy consiting of 1 to 20% In, 0.5 to 15% Sm, and from 3 to 18% Hf, the balance being Ni. Such alloys show a good absorption capacity for thermal and intermediate neutrons, good neutron capture efficiency, and good corrosion resistance, and find application in nuclear reactor automatic control and safety systems. The Hf provides for the maintenance of a reasonably high order of neutron capture efficiency throughout the lifetime of a reactor. The alloys are formed in a vacuum furnace operating with an inert gas atmosphere at 280 to 300 mm.Hg. They have a corrosion resistance from 3 to 3.5 times that of the Ag-based alloys commonly employed, and a neutron capture efficiency about twice that of the Ag alloys. Castability and structural strength are good. (U.K.)

  1. Temperature measurement with neutrons

    International Nuclear Information System (INIS)

    Bizard, G.; Durand, D.; Lecolley, J.F.; Lefebvres, F.; Marques, M.; Peter, J.; Tamain, B.

    1998-01-01

    The results presented in this report were obtained from the information provided by charged products. Another alternative consists in detecting the neutrons abundantly emitted particularly by heavy nuclei. The residue channel was studied in the 40 Ar + 197 Au at 60 MeV/nucleon by means of the neutron multidetector DEMON. The evolution of the multiplicity of neutrons emitted backwards in the framework of the heavy nucleus forwardly detected as a function of the residue velocity by a silicon detector, placed at 8 degrees and at 24.5 cm from target, agrees with the expected results i.e. an increase with the residue velocity hence with the collision violence. For the same detector the first measurements show similarly a linear increase of the apparent temperature of 4.0 to around 6.5 MeV for residue velocities varying from 0.5 to 1.3 cm/ns and masses ranging from 140 to 160 uma. This first results of the analysis show therefore a good behaviour of the assembly and especially of the couple DeMoN-SyReP

  2. Neutron reflectometry

    International Nuclear Information System (INIS)

    Van Well, A.A.

    1999-01-01

    Neutron research where reflection, refraction, and interference play an essential role is generally referred to as 'neutron optics'. The neutron wavelength, the scattering length density and the magnetic properties of the material determine the critical angle for total reflection. The theoretical background of neutron reflection, experimental methods and the interpretation of reflection data are presented. (K.A.)

  3. Development of an operational neutron spectrometry system dedicated to the characterization of the natural atmospheric radiative environment, implemented at the Pic du Midi

    International Nuclear Information System (INIS)

    Cheminet, Adrien

    2013-01-01

    This PhD Thesis has been achieved thanks to the joint effort between two French organizations, the French Institute for Radiological Protection and Nuclear Safety (IRSN/LMDN, Cadarache) and the French Aerospace Lab (ONERA/ DESP, Toulouse). The aim was to develop an operational neutron spectrometer extended to high energies in order to measure the dynamics of the spectral variations of the natural radiative environment at the summit of the Pic du Midi Observatory in the French Pyrenees. Thereby, the fluence responses of each detector were calculated thanks to Monte Carlo simulations. Afterwards, they were validated by means of experimental campaigns up to high energies (≥20 MeV) nearby reference neutron fields. The systematic uncertainties were deduced after detailed studies of the mathematic reconstruction of the spectra (i.e. unfolding procedure). Then, the system was tested under rocks at the LSBB of Rustrel before being installed at respectively +500 m and +1000 m above sea level for the first environmental campaigns. Finally, the spectrometer has been operating for two years after its deployment at the summit of the Pic du Midi (+2885 m). The continuous data were analysed thanks to an innovative method. Some seasonal and spectral variations were observed. Some Forbush decreases were also recorded after strong solar flares. These data were further analysed thanks to Monte Carlo simulations. The data were made more attractive thanks to several practical applications with personnel dosimetry or reliability of submicron electronics components. (author)

  4. Neutron radiography with ultracold neutrons

    International Nuclear Information System (INIS)

    Bates, J.C.

    1981-01-01

    The neutron transmission factor of very thin films may be low if the neutron energy is comparable to the pseudo-potential of the film material. Surprisingly, perhaps, it is relatively easy to obtain neutrons with such low energies in sufficient numbers to produce neutron radiographs. (orig.)

  5. Measurement for skyshine of neutron generated by the K-600 neutron generator

    International Nuclear Information System (INIS)

    Zhen Huazhi; Li Guisheng; Wu Jingmin; Li Jianping

    1988-01-01

    The attenuation low of neutron scattering in atmosphere that generated by K-600 neutron generator at IMP was measured in order to evaluate the effect of the neutron generator to surroundings. The attenuation lenth λ = 396m was obtained and this result is in aggreement with the measured data at some laboratories abroad

  6. Neutron beam applications

    International Nuclear Information System (INIS)

    Lee, Chang Hee; Lee, J. S.; Seong, B. S.

    2000-05-01

    For the materials science by neutron technique, the development of the various complementary neutron beam facilities at horizontal beam port of HANARO and the techniques for measurement and analysis has been performed. High resolution powder diffractometer, after the installation and performance test, has been opened and used actively for crystal structure analysis, magnetic structure analysis, phase transition study, etc., since January 1998. The main components for four circle diffractometer were developed and, after performance test, it has been opened for crystal structure analysis and texture measurement since the end of 1999. For the small angle neutron spectrometer, the main component development and test, beam characterization, and the preliminary experiment for the structure study of polymer have been carried out. Neutron radiography facility, after the precise performance test, has been used for the non-destructive test of industrial component. Addition to the development of main instruments, for the effective utilization of those facilities, the scattering techniques relating to quantitative phase analysis, magnetic structure analysis, texture measurement, residual stress measurement, polymer study, etc, were developed. For the neutron radiography, photographing and printing technique on direct and indirect method was stabilized and the development for the real time image processing technique by neutron TV was carried out. The sample environment facilities for low and high temperature, magnetic field were also developed

  7. Comparison of the atmospheric- and reduced-pressure HS-SPME strategies for analysis of residual solvents in commercial antibiotics using a steel fiber coated with a multiwalled carbon nanotube/polyaniline nanocomposite.

    Science.gov (United States)

    Ghiasvand, Ali Reza; Nouriasl, Kolsoum; Yazdankhah, Fatemeh

    2018-01-01

    A low-cost, sensitive and reliable reduced-pressure headspace solid-phase microextraction (HS-SPME) setup was developed and evaluated for direct extraction of residual solvents in commercial antibiotics, followed by determination by gas chromatography with flame ionization detection (GC-FID). A stainless steel narrow wire was made porous and adhesive by platinization by a modified electrophoretic deposition method and coated with a polyaniline/multiwalled carbon nanotube nanocomposite. All experimental variables affecting the extraction efficiency were investigated for both atmospheric-pressure and reduced-pressure conditions. Comparison of the optimal experimental conditions and the results demonstrated that the reduced-pressure strategy leads to a remarkable increase in the extraction efficiency and reduction of the extraction time and temperature (10 min, 25 °Ϲ vs 20 min, 40 °Ϲ). Additionally, the reduced-pressure strategy showed better analytical performances compared with those obtained by the conventional HS-SPME-GC-FID method. Limit of detections, linear dynamic ranges, and relative standard deviations of the reduced-pressure HS-SPME procedure for benzene, toluene, ethylbenzene, and xylene (BTEX) in injectable solid drugs were obtained over the ranges of 20-100 pg g -1 , 0.02-40 μg g -1 , and 2.8-10.2%, respectively. The procedure developed was successful for the analysis of BTEX in commercial containers of penicillin, ampicillin, ceftriaxone, and cefazolin. Graphical abstract Schematic representation of the developed RP-HS-SPME setup.

  8. Neutron Skins and Neutron Stars

    OpenAIRE

    Piekarewicz, J.

    2013-01-01

    The neutron-skin thickness of heavy nuclei provides a fundamental link to the equation of state of neutron-rich matter, and hence to the properties of neutron stars. The Lead Radius Experiment ("PREX") at Jefferson Laboratory has recently provided the first model-independence evidence on the existence of a neutron-rich skin in 208Pb. In this contribution we examine how the increased accuracy in the determination of neutron skins expected from the commissioning of intense polarized electron be...

  9. Neutron Dosimetry

    International Nuclear Information System (INIS)

    Vanhavere, F.

    2001-01-01

    The objective of SCK-CEN's R and D programme on neutron dosimetry is to improve the determination of neutron doses by studying neutron spectra, neutron dosemeters and shielding adaptations. In 2000, R and D focused on the contiued investigation of the bubble detectors type BD-PND and BDT, in particular their sensitivity and temperature dependence; the updating of SCK-CEN's criticality dosemeter, the investigation of the characteristics of new thermoluminescent materials and their use in neutron dosemetry; and the investigation of neutron shielding

  10. Neutron Dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Vanhavere, F

    2001-04-01

    The objective of SCK-CEN's R and D programme on neutron dosimetry is to improve the determination of neutron doses by studying neutron spectra, neutron dosemeters and shielding adaptations. In 2000, R and D focused on the contiued investigation of the bubble detectors type BD-PND and BDT, in particular their sensitivity and temperature dependence; the updating of SCK-CEN's criticality dosemeter, the investigation of the characteristics of new thermoluminescent materials and their use in neutron dosemetry; and the investigation of neutron shielding.

  11. Neutron radiography

    International Nuclear Information System (INIS)

    Hrdlicka, Z.

    1977-01-01

    Neutron radiography is a radiographic method using a neutron beam of a defined geometry. The neutron source usually consists of a research reactor, a specialized neutron radiography reactor or the 252 Cf radioisotope source. There are two types of the neutron radiography display system, viz., a system producing neutron radiography images by a photographic process or a system allowing a visual display, eg., using a television monitor. The method can be used wherever X-ray radiography is used except applications in the radiography of humans. The neutron radiography unit at UJV uses the WWR-S reactor as the neutron source and both types of the above mentioned display system. (J.P.)

  12. The neutron

    International Nuclear Information System (INIS)

    Kredov, B.M.

    1979-01-01

    The history of the neutron is displayed on the basis of contributions by scientists who produced outstanding results in neutron research (part 1), of summarizing discoveries and theories which led to the discovery of the neutron and the resulting development of nuclear physics (part 2), and of fundamental papers written by Rutherford, Chadwick, Iwanenko, and others (appendix). Of interest to physicists, historians, and students

  13. Neutron techniques

    International Nuclear Information System (INIS)

    Charlton, J.S.

    1986-01-01

    The way in which neutrons interact with matter such as slowing-down, diffusion, neutron absorption and moderation are described. The use of neutron techniques in industry, in moisture gages, level and interface measurements, the detection of blockages, boron analysis in ore feedstock and industrial radiography are discussed. (author)

  14. U.S. Isostatic Residual Gravity Grid

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — isores.bin - standard grid containing isostatic residual gravity map for U.S. Grid interval = 4 km. Projection is Albers (central meridian = 96 degrees West; base...

  15. Residual basins

    International Nuclear Information System (INIS)

    D'Elboux, C.V.; Paiva, I.B.

    1980-01-01

    Exploration for uranium carried out over a major portion of the Rio Grande do Sul Shield has revealed a number of small residual basins developed along glacially eroded channels of pre-Permian age. Mineralization of uranium occurs in two distinct sedimentary units. The lower unit consists of rhythmites overlain by a sequence of black shales, siltstones and coal seams, while the upper one is dominated by sandstones of probable fluvial origin. (Author) [pt

  16. The nev diffractometer ARES for the analysis of residual stresses

    Czech Academy of Sciences Publication Activity Database

    Staron, P.; Ruhnau, H. U.; Marmotti, M.; Mikula, Pavol; Kampmann, R.

    276/278, - (2000), s. 158-159 ISSN 0921-4526 Institutional research plan: CEZ:AV0Z1048901 Keywords : neutron instruments * residual stress Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.893, year: 2000

  17. Neutron radiography

    International Nuclear Information System (INIS)

    Hiraoka, Eiichi

    1988-01-01

    The thermal neutron absorption coefficient is essentially different from the X-ray absorption coefficient. Each substance has a characteristic absorption coefficient regardless of its density. Neutron deams have the following features: (1) neutrons are not transmitted efficiently by low molecular weight substances, (2) they are transmitted efficiently by heavy metals, and (3) the transmittance differs among isotopes. Thus, neutron beams are suitable for cheking for foreign matters in heavy metals and testing of composites consisting of both heavy and light materials. A neutron source generates fast neutrons, which should be converted into thermal neutrons by reducing their energy. Major neutron souces include nuclear reactors, radioisotopes and particle accelerators. Photographic films and television systems are mainly used to observe neutron transmission images. Computers are employed for image processing, computerized tomography and three-dimensional analysis. The major applications of neutron radiography include inspection of neclear fuel; evaluation of material for airplane; observation of fuel in the engine and oil in the hydraulic systems in airplanes; testing of composite materials; etc. (Nogami, K.)

  18. Characterization of residual stresses generated during inhomogeneous plastic deformation

    DEFF Research Database (Denmark)

    Lorentzen, T.; Faurholdt, T.; Clausen, B.

    1998-01-01

    Residual stresses generated by macroscopic inhomogeneous plastic deformation are predicted by an explicit finite element (FE) technique. The numerical predictions are evaluated by characterizing the residual elastic strains by neutron diffraction using two different (hkl) reflections. Intergranular...... compare well and verify the capability of the numerical technique as well as the possibilities of experimental validation using neutron diffraction. The presented experimental and numerical approach will subsequently be utilized for the evaluation of more complicated plastic deformation processes...

  19. Staging atmospheres

    DEFF Research Database (Denmark)

    Bille, Mikkel; Bjerregaard, Peter; Sørensen, Tim Flohr

    2015-01-01

    The article introduces the special issue on staging atmospheres by surveying the philosophical, political and anthropological literature on atmosphere, and explores the relationship between atmosphere, material culture, subjectivity and affect. Atmosphere seems to occupy one of the classic...

  20. Neutron detector

    Science.gov (United States)

    Stephan, Andrew C [Knoxville, TN; Jardret,; Vincent, D [Powell, TN

    2011-04-05

    A neutron detector has a volume of neutron moderating material and a plurality of individual neutron sensing elements dispersed at selected locations throughout the moderator, and particularly arranged so that some of the detecting elements are closer to the surface of the moderator assembly and others are more deeply embedded. The arrangement captures some thermalized neutrons that might otherwise be scattered away from a single, centrally located detector element. Different geometrical arrangements may be used while preserving its fundamental characteristics. Different types of neutron sensing elements may be used, which may operate on any of a number of physical principles to perform the function of sensing a neutron, either by a capture or a scattering reaction, and converting that reaction to a detectable signal. High detection efficiency, an ability to acquire spectral information, and directional sensitivity may be obtained.

  1. Fusion neutronics

    CERN Document Server

    Wu, Yican

    2017-01-01

    This book provides a systematic and comprehensive introduction to fusion neutronics, covering all key topics from the fundamental theories and methodologies, as well as a wide range of fusion system designs and experiments. It is the first-ever book focusing on the subject of fusion neutronics research. Compared with other nuclear devices such as fission reactors and accelerators, fusion systems are normally characterized by their complex geometry and nuclear physics, which entail new challenges for neutronics such as complicated modeling, deep penetration, low simulation efficiency, multi-physics coupling, etc. The book focuses on the neutronics characteristics of fusion systems and introduces a series of theories and methodologies that were developed to address the challenges of fusion neutronics, and which have since been widely applied all over the world. Further, it introduces readers to neutronics design’s unique principles and procedures, experimental methodologies and technologies for fusion systems...

  2. Neutron spectometers

    International Nuclear Information System (INIS)

    Poortmans, F.

    1977-01-01

    Experimental work in the field of low-energy neutron physics can be subdivided into two classes: 1)Study of the decay process of the compound-nucleus state as for example the study of the capture gamma rays and of the neutron induced fission process; 2)Study of the reaction mechanism, mainly by measuring the reaction cross-sections and resonance parameters. These neutron cross-sections and resonance parameters are also important data required for many technological applications especially for reactor development programmes. In general, the second class of experiments impose other requirements on the neutron spectrometer than the first class. In most cases, a better neutron energy resolution and a broader neutron energy range are required for the study of the reaction mechanism than for the study of various aspects of the decay process. (author)

  3. Martian Neutron Energy Spectrometer (MANES)

    Science.gov (United States)

    Maurer, R. H.; Roth, D. R.; Kinnison, J. D.; Goldsten, J. O.; Fainchtein, R.; Badhwar, G.

    2000-01-01

    High energy charged particles of extragalactic, galactic, and solar origin collide with spacecraft structures and planetary atmospheres. These primaries create a number of secondary particles inside the structures or on the surfaces of planets to produce a significant radiation environment. This radiation is a threat to long term inhabitants and travelers for interplanetary missions and produces an increased risk of carcinogenesis, central nervous system (CNS) and DNA damage. Charged particles are readily detected; but, neutrons, being electrically neutral, are much more difficult to monitor. These secondary neutrons are reported to contribute 30-60% of the dose equivalent in the Shuttle and MIR station. The Martian atmosphere has an areal density of 37 g/sq cm primarily of carbon dioxide molecules. This shallow atmosphere presents fewer mean free paths to the bombarding cosmic rays and solar particles. The secondary neutrons present at the surface of Mars will have undergone fewer generations of collisions and have higher energies than at sea level on Earth. Albedo neutrons produced by collisions with the Martian surface material will also contribute to the radiation environment. The increased threat of radiation damage to humans on Mars occurs when neutrons of higher mean energy traverse the thin, dry Martian atmosphere and encounter water in the astronaut's body. Water, being hydrogeneous, efficiently moderates the high energy neutrons thereby slowing them as they penetrate deeply into the body. Consequently, greater radiation doses can be deposited in or near critical organs such as the liver or spleen than is the case on Earth. A second significant threat is the possibility of a high energy heavy ion or neutron causing a DNA double strand break in a single strike.

  4. Compact neutron generator with nanotube ion source

    Science.gov (United States)

    Chepurnov, A. S.; Ionidi, V. Y.; Ivashchuk, O. O.; Kirsanov, M. A.; Kitsyuk, E. P.; Klenin, A. A.; Kubankin, A. S.; Nazhmudinov, R. M.; Nikulin, I. S.; Oleinik, A. N.; Pavlov, A. A.; Shchagin, A. V.; Zhukova, P. N.

    2018-02-01

    In this letter, we report the observation of fast neutrons generated when a positive acceleration potential is applied to an array of orientated carbon nanotubes, which are used as an ion source. The neutrons with energy of 2.45 MeV are generated as a result of D-D fusion reaction. The dependencies of the neutron yield on the value of the applied potential and residual pressure of deuterium are measured. The proposed approach is planned to be used for the development of compact neutron generators.

  5. Neutron exposure

    International Nuclear Information System (INIS)

    Prillinger, G.; Konynenburg, R.A. van

    1998-01-01

    As a result of the popularity of the Agencies report 'Neutron Irradiation Embrittlement of Reactor Pressure Vessel Steels' of 1975, it was decided that another report on this broad subject would be of use. In this report, background and contemporary views on specially identified areas of the subject are considered as self-contained chapters, written by experts. In chapter 6, LWR-PV neutron transport calculations and dosimetry methods and how they are combined to evaluate the neutron exposure of the steel of pressure vessels are discussed. An effort to correlate neutron exposure parameters with damage is made

  6. Neutron Albedo

    CERN Document Server

    Ignatovich, V K

    2005-01-01

    A new, algebraic, method is applied to calculation of neutron albedo from substance to check the claim that use of ultradispersive fuel and moderator of an active core can help to gain in size and mass of the reactor. In a model of isotropic distribution of incident and reflected neutrons it is shown that coherent scattering on separate grains in the case of thermal neutrons increases transport cross section negligibly, however it decreases albedo from a wall of finite thickness because of decrease of substance density. A visible increase of albedo takes place only for neutrons with wave length of the order of the size of a single grain.

  7. Neutron dosimetry; Dosimetria de neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Fratin, Luciano

    1993-12-31

    A neutron irradiation facility was designed and built in order to establish a procedure for calibrating neutron monitors and dosemeters. A 185 GBq {sup 241} Am Be source of known is used as a reference source. The irradiation facility using this source in the air provides neutron dose rates between 9 nSv s{sup -1} and 0,5 {sup {mu}}Sv s{sup -1}. A calibrated 50 nSv s{sup -1} thermal neutron field is obtained by using a specially designed paraffin block in conjunction with the {sup 241} Am Be source. A Bonner multisphere spectrometer was calibrated, using a procedure based on three methods proposed by international standards. The unfold {sup 241} Am Be neutron spectrum was determined from the Bonner spheres data and resulted in a good agreement with expected values for fluence rate, dose rate and mean energy. A dosimetric system based on the electrochemical etching of CR-39 was developed for personal dosimetry. The dosemeter badge using a (n,{alpha}) converter, the etching chamber and high frequency power supply were designed and built specially for this project. The electrochemical etching (ECE) parameters used were: a 6N KOH solution, 59 deg C, 20 kV{sub pp} cm{sup -1}, 2,0 kHz, 3 hours of ECE for thermal and intermediate neutrons and 6 hours for fast neutrons. The calibration factors for thermal, intermediate and fast neutrons were determined for this personal dosemeter. The sensitivities determined for the developed dosimetric system were (1,46{+-} 0,09) 10{sup 4} tracks cm{sup -2} mSv{sup -1} for thermal neutrons, (9{+-}3) 10{sup 2} tracks cm{sup -2} mSV{sup -1} for intermediate neutrons and (26{+-}4) tracks cm{sup -2} mSv{sup -1} for fast neutrons. The lower and upper limits of detection were respectively 0,002 mSv and 0,6 mSv for thermal neutrons, 0,04 mSv and 8 mSv for intermediate neutrons and 1 mSv and 12 mSv for fast neutrons. In view of the 1990`s ICRP recommendations, it is possible to conclude that the personal dosemeter described in this work is

  8. Neutron dosimetry; Dosimetria de neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Fratin, Luciano

    1994-12-31

    A neutron irradiation facility was designed and built in order to establish a procedure for calibrating neutron monitors and dosemeters. A 185 GBq {sup 241} Am Be source of known is used as a reference source. The irradiation facility using this source in the air provides neutron dose rates between 9 nSv s{sup -1} and 0,5 {sup {mu}}Sv s{sup -1}. A calibrated 50 nSv s{sup -1} thermal neutron field is obtained by using a specially designed paraffin block in conjunction with the {sup 241} Am Be source. A Bonner multisphere spectrometer was calibrated, using a procedure based on three methods proposed by international standards. The unfold {sup 241} Am Be neutron spectrum was determined from the Bonner spheres data and resulted in a good agreement with expected values for fluence rate, dose rate and mean energy. A dosimetric system based on the electrochemical etching of CR-39 was developed for personal dosimetry. The dosemeter badge using a (n,{alpha}) converter, the etching chamber and high frequency power supply were designed and built specially for this project. The electrochemical etching (ECE) parameters used were: a 6N KOH solution, 59 deg C, 20 kV{sub pp} cm{sup -1}, 2,0 kHz, 3 hours of ECE for thermal and intermediate neutrons and 6 hours for fast neutrons. The calibration factors for thermal, intermediate and fast neutrons were determined for this personal dosemeter. The sensitivities determined for the developed dosimetric system were (1,46{+-} 0,09) 10{sup 4} tracks cm{sup -2} mSv{sup -1} for thermal neutrons, (9{+-}3) 10{sup 2} tracks cm{sup -2} mSV{sup -1} for intermediate neutrons and (26{+-}4) tracks cm{sup -2} mSv{sup -1} for fast neutrons. The lower and upper limits of detection were respectively 0,002 mSv and 0,6 mSv for thermal neutrons, 0,04 mSv and 8 mSv for intermediate neutrons and 1 mSv and 12 mSv for fast neutrons. In view of the 1990`s ICRP recommendations, it is possible to conclude that the personal dosemeter described in this work is

  9. Synthesis and characterization of brannerite wasteforms for the immobilization of mixed oxide fuel residues

    Energy Technology Data Exchange (ETDEWEB)

    Bailey, D.J.; Stennett, M.C.; Hyatt, N.C. [Immobilisation Science Laboratory, Department of Materials Science and Engineering, University of Sheffield, Sheffield, S1 3JD (United Kingdom)

    2016-07-01

    A possible method for the reduction of civil Pu stockpiles is the reuse of Pu in mixed oxide fuel (MOX). During MOX fuel production, residues unsuitable for further recycle will be produced. Due to their high actinide content MOX residues require immobilization within a robust host matrix. Although it is possible to immobilize actinides in vitreous wasteforms; ceramic phases, such as brannerite (UTi{sub 2}O{sub 6}), are attractive due to their high waste loading capacity and relative insolubility. A range of uranium brannerite, formulated Gd{sub x}U{sub 1-x}Ti{sub 2}O{sub 6}, were prepared using a mixed oxide route. Charge compensation of divalent and trivalent cations was expected to occur via the oxidation of U{sup 4+} to higher valence states (U{sup 5+} or U{sup 6+}). Gd{sup 3+} was added to act as a neutron absorber in the final Pu bearing wasteform. X-ray powder diffraction of synthesised specimens found that phase distribution was strongly affected by processing atmosphere (air or Ar). In all cases prototypical brannerite was formed accompanied by different secondary phases dependent on processing atmosphere. Microstructural analysis (SEM) of the sintered samples confirmed the results of the X-ray powder diffraction. The preliminary results presented here indicate that brannerite is a promising host matrix for mixed oxide fuel residues. (authors)

  10. Neutronic reactor

    International Nuclear Information System (INIS)

    Wende, C.W.J.

    1976-01-01

    A safety rod for a nuclear reactor has an inner end portion having a gamma absorption coefficient and neutron capture cross section approximately equal to those of the adjacent shield, a central portion containing materials of high neutron capture cross section and an outer end portion having a gamma absorption coefficient at least equal to that of the adjacent shield

  11. Neutron polarization

    International Nuclear Information System (INIS)

    Firk, F.W.K.

    1976-01-01

    Some recent experiments involving polarized neutrons are discussed; they demonstrate how polarization studies provide information on fundamental aspects of nuclear structure that cannot be obtained from more traditional neutron studies. Until recently, neutron polarization studies tended to be limited either to very low energies or to restricted regions at higher energies, determined by the kinematics of favorable (p, vector n) and (d, vector n) reactions. With the advent of high intensity pulsed electron and proton accelerators and of beams of vector polarized deuterons, this is no longer the case. One has entered an era in which neutron polarization experiments are now being carried out, in a routine way, throughout the entire range from thermal energies to tens-of-MeV. The significance of neutron polarization studies is illustrated in discussions of a wide variety of experiments that include the measurement of T-invariance in the β-decay of polarized neutrons, a search for the effects of meson exchange currents in the photo-disintegration of the deuteron, the determination of quantum numbers of states in the fission of aligned 235 U and 237 Np induced by polarized neutrons, and the double- and triple-scattering of fast neutrons by light nuclei

  12. Neutron holography

    International Nuclear Information System (INIS)

    Beynon, T.D.

    1986-01-01

    the paper concerns neutron holography, which allows an image to be constructed of the surfaces, as well as the interiors, of objects. The technique of neutron holography and its applications are described. Present and future use of the method is briefly outlined. (U.K.)

  13. Residual nilpotence and residual solubility of groups

    International Nuclear Information System (INIS)

    Mikhailov, R V

    2005-01-01

    The properties of the residual nilpotence and the residual solubility of groups are studied. The main objects under investigation are the class of residually nilpotent groups such that each central extension of these groups is also residually nilpotent and the class of residually soluble groups such that each Abelian extension of these groups is residually soluble. Various examples of groups not belonging to these classes are constructed by homological methods and methods of the theory of modules over group rings. Several applications of the theory under consideration are presented and problems concerning the residual nilpotence of one-relator groups are considered.

  14. Neutron source

    International Nuclear Information System (INIS)

    Cason, J.L. Jr.; Shaw, C.B.

    1975-01-01

    A neutron source which is particularly useful for neutron radiography consists of a vessel containing a moderating media of relatively low moderating ratio, a flux trap including a moderating media of relatively high moderating ratio at the center of the vessel, a shell of depleted uranium dioxide surrounding the moderating media of relatively high moderating ratio, a plurality of guide tubes each containing a movable source of neutrons surrounding the flux trap, a neutron shield surrounding one part of each guide tube, and at least one collimator extending from the flux trap to the exterior of the neutron source. The shell of depleted uranium dioxide has a window provided with depleted uranium dioxide shutters for each collimator. Reflectors are provided above and below the flux trap and on the guide tubes away from the flux trap

  15. Neutron transport

    International Nuclear Information System (INIS)

    Berthoud, Georges; Ducros, Gerard; Feron, Damien; Guerin, Yannick; Latge, Christian; Limoge, Yves; Santarini, Gerard; Seiler, Jean-Marie; Vernaz, Etienne; Coste-Delclaux, Mireille; M'Backe Diop, Cheikh; Nicolas, Anne; Andrieux, Catherine; Archier, Pascal; Baudron, Anne-Marie; Bernard, David; Biaise, Patrick; Blanc-Tranchant, Patrick; Bonin, Bernard; Bouland, Olivier; Bourganel, Stephane; Calvin, Christophe; Chiron, Maurice; Damian, Frederic; Dumonteil, Eric; Fausser, Clement; Fougeras, Philippe; Gabriel, Franck; Gagnier, Emmanuel; Gallo, Daniele; Hudelot, Jean-Pascal; Hugot, Francois-Xavier; Dat Huynh, Tan; Jouanne, Cedric; Lautard, Jean-Jacques; Laye, Frederic; Lee, Yi-Kang; Lenain, Richard; Leray, Sylvie; Litaize, Olivier; Magnaud, Christine; Malvagi, Fausto; Mijuin, Dominique; Mounier, Claude; Naury, Sylvie; Nicolas, Anne; Noguere, Gilles; Palau, Jean-Marc; Le Pallec, Jean-Charles; Peneliau, Yannick; Petit, Odile; Poinot-Salanon, Christine; Raepsaet, Xavier; Reuss, Paul; Richebois, Edwige; Roque, Benedicte; Royer, Eric; Saint-Jean, Cyrille de; Santamarina, Alain; Serot, Olivier; Soldevila, Michel; Tommasi, Jean; Trama, Jean-Christophe; Tsilanizara, Aime; Behar, Christophe; Provitina, Olivier; Lecomte, Michael; Forestier, Alain; Bender, Alexandra; Parisot, Jean-Francois; Finot, Pierre

    2013-10-01

    This bibliographical note presents a reference book which addresses the study of neutron transport in matter, the study of conditions for a chain reaction and the study of modifications of matter composition due to nuclear reactions. This book presents the main nuclear data, their measurement, assessment and processing, and the spallation. It proposes an overview of methods applied for the study of neutron transport: basic equations and their derived forms, deterministic methods and Monte Carlo method of resolution of the Boltzmann equation, methods of resolution of generalized Bateman equations, methods of time resolution of space kinetics coupled equations. It presents the main calculation codes, discusses the qualification and experimental aspects, and gives an overview of neutron transport applications: neutron transport calculation of reactors, neutron transport coupled with other disciplines, physics of fuel cycle, criticality

  16. Jovian atmospheres

    International Nuclear Information System (INIS)

    Allison, M.; Travis, L.D.

    1986-10-01

    A conference on the atmosphere of Jupiter produced papers in the areas of thermal and ortho-para hydrogen structure, clouds and chemistry, atmospheric structure, global dynamics, synoptic features and processes, atmospheric dynamics, and future spaceflight opportunities. A session on the atmospheres of Uranus and Neptune was included, and the atmosphere of Saturn was discussed in several papers

  17. Hybrid scintillators for neutron discrimination

    Science.gov (United States)

    Feng, Patrick L; Cordaro, Joseph G; Anstey, Mitchell R; Morales, Alfredo M

    2015-05-12

    A composition capable of producing a unique scintillation response to neutrons and gamma rays, comprising (i) at least one surfactant; (ii) a polar hydrogen-bonding solvent; and (iii) at least one luminophore. A method including combining at least one surfactant, a polar hydrogen-bonding solvent and at least one luminophore in a scintillation cell under vacuum or an inert atmosphere.

  18. Neutron scattering in Indonesia. Country report

    Energy Technology Data Exchange (ETDEWEB)

    Ikram, Abarrul [Neutron Scattering Laboratory, R and D Center for Materials Science and Technology, National Nuclear Energy Agency, Serpong (Indonesia)

    2000-10-01

    Neutron scattering in Indonesia is still alienated due to some reasons and conditions which are discussed. The reactor and its latest operation mode are also described. The neutron beam facilities which include one diffractometer for residual stress measurement, one diffractometer for single crystal structural determination and texture measurement, one high resolution powder diffractometer, one neutron radiography facility, one triple axis spectrometer, one small angle neutron scattering spectrometer and one high resolution small angle neutron scattering spectrometer were presented briefly together with improvements of neutron intensities at some spectrometers in connection with the setting of main beam shutter position. Special attention is given for four instruments mostly related to this workshop. Their performances and problems faced in the past 9 months are presented as well as the future plan for refurbishment and development. (author)

  19. Neutron therapy

    International Nuclear Information System (INIS)

    Riesler, Rudi

    1995-01-01

    Standard radiotherapy uses Xrays or electrons which have low LET (linear energy transfer); in contrast, particles such as neutrons with high LET have different radiobiological responses. In the late 1960s, clinical trials by Mary Catterall at the Hammersmith Hospital in London indicated that fast neutron radiation had clinical advantages for certain malignant tumours. Following these early clinical trials, several cyclotron facilities were built in the 1980s for fast neutron therapy, for example at the University of Washington, Seattle, and at UCLA. Most of these newer machines use extracted cyclotron proton beams in the range 42 to 66 MeV with beam intensities of 15 to 60 microamps. The proton beams are transported to dedicated therapy rooms, where neutrons are produced from beryllium targets. Second-generation clinical trials showed that accurate neutron beam delivery to the tumour site is more critical than for photon therapy. In order to achieve precise beam geometries, the extracted proton beams have to be transported through a gantry which can rotate around the patient and deliver beams from any angle; also the neutron beam outline (''field shape'') must be adjusted to extremely irregular shapes using a flexible collimation system. A therapy procedure has to be appropriately organized, with physicians, radiotherapists, nurses, medical physicists and other staff in attendance; other specialized equipment, such as CT or MRI scanners and radiation simulators must be made available. Neutron therapy is usually performed only in radiation oncology departments of major medical centres

  20. Neutron radiography

    International Nuclear Information System (INIS)

    Alaa eldin, M.T.

    2011-01-01

    The digital processing of the neutron radiography images gives the possibility for data quantification. In this case an exact relation between the measured neutron attenuation and the real macroscopic attenuation coefficient for every point of the sample is required. The assumption that the attenuation of the neutron beam through the sample is exponential is valid only in an ideal case where a monochromatic beam, non scattering sample and non background contribution are assumed. In the real case these conditions are not fulfilled and in dependence on the sample material we have more or less deviation from the exponential attenuation law. Because of the high scattering cross-sections of hydrogen (σs=80.26 barn) for thermal neutrons, the problem with the scattered neutrons at quantitative radiography investigations of hydrogenous materials (as PE, Oil, H 2 O, etc) is not trivial. For these strong scattering materials the neutron beam attenuation is no longer exponential and a dependence of the macroscopic attenuation coefficient on the material thickness and on the distance between the sample and the detector appears. When quantitative radiography (2 D) or tomography investigations (3 D) are performed, some image correction procedures for a description of the scattering effect are required. This thesis presents a method that can be used to enhance the neutron radiography image for objects with high scattering materials like hydrogen, carbon and other light materials. This method uses the Monte Carlo code, MCNP5, to simulate the neutron radiography process and get the flux distribution for each pixel of the image and determine the scattered neutrons distribution that causes the image blur and then subtract it from the initial image to improve its quality.

  1. Gold processing residue from Jacobina Basin: chemical and physical properties

    OpenAIRE

    Lima, Luiz Rogério Pinho de Andrade; Bernardez, Letícia Alonso; Barbosa, Luís Alberto Dantas

    2007-01-01

    p. 848-852 Gold processing residues or tailings are found in several areas in the Itapicuru River region (Bahia, Brazil), and previous studies indicated significant heavy metals content in the river sediments. The present work focused on an artisanal gold processing residue found in a site from this region. Samples were taken from the processing residue heaps and used to perform a physical and chemical characterization study using X-ray diffraction, scanning electron microscopy, neutron...

  2. Neutronics codes

    International Nuclear Information System (INIS)

    Buckel, G.

    1983-01-01

    The objectives are the development, testing and cultivation of reliable, efficient and user-optimized neutron-physical calculation methods and conformity with users' requirements concerning design of power reactors, planning and analysis of experiments necessary for their protection as well as research on physical key problems. A short outline of available computing programmes for the following objectives is given: - Provision of macroscopic group constants, - Calculation of neutron flux distribution in transport theory and diffusion approximation, - Evaluation of neutron flux-distribution, - Execution of disturbance calculations for the determination reactivity coefficients, and - graphical representation of results. (orig./RW) [de

  3. Neutron reflectometry

    DEFF Research Database (Denmark)

    Klösgen-Buchkremer, Beate Maria

    2014-01-01

    of desired information. In the course, an introduction into the method and an overview on selected instruments at large scale facilities will be presented. Examples will be given that illustrate the potential of the method, mostly based on organic films. Results from the investigation of layered films......Neutron (and X-ray) reflectometry constitute complementary interfacially sensitive techniques that open access to studying the structure within thin films of both soft and hard condensed matter. Film thickness starts oxide surfaces on bulk substrates, proceeding to (pauci-)molecular layers and up...... films or films with magnetic properties. The reason is the peculiar property of neutron light since the mass of a neutron is close to the one of a proton, and since it bears a magnetic moment. The optical properties of matter, when interacting with neutrons, are described by a refractive index...

  4. Neutron scattering

    International Nuclear Information System (INIS)

    Furrer, A.

    1993-01-01

    This report contains the text of 16 lectures given at the Summer School and the report on a panel discussion entitled ''the relative merits and complementarities of x-rays, synchrotron radiation, steady- and pulsed neutron sources''. figs., tabs., refs

  5. Neutron storage

    International Nuclear Information System (INIS)

    Strelkov, A.V.

    2004-01-01

    The report is devoted to neutron storage (NS) and describes the history of experiments on the NS development. Great attention is paid to ultracold neutron (UCN) storage. The experiments on the UCN generation, transport, spectroscopy, storage and detection are described. Experiments on searching the UCN electric-dipole moment and electric charge are continued. Possible using of UCN for studying the nanoparticles is discussed [ru

  6. Neutron radiography

    International Nuclear Information System (INIS)

    Bayon, G.

    1989-01-01

    Neutronography or neutron radiography, a non-destructive test method which is similar in its principle to conventional X-ray photography, presently occupies a marginal position among non-destructive test methods (NDT) (no source of suitable performance or cost). Neutron radiography associated with the ORPHEE reactor permits industrial testing; it can very quickly meet a cost requirement comparable to that of conventional test methods. In 1988, 2500 parts were tested on this unit [fr

  7. Automated monitoring of fissile and fertile materials in incinerator residue

    International Nuclear Information System (INIS)

    Schoenig, F.C. Jr.; Glendinning, S.G.; Tunnell, G.W.; Zucker, M.S.

    1986-01-01

    This patent describes an apparatus for determining the fissile and fertile material content of incinerator residue contained in a manipulatable container. The apparatus comprises a main body member formed of neutron moderating material and formed with a well for receiving the container; a first plug formed of neutron reflecting material for closing the top of the well; and a second plug containing a first neutron source for alternatively closing the top of the well and for directing neutrons into the well. It also includes a second neutron source selectively positionable in the bottom of the well for directing neutrons into the well; manipulating means for placing the container in the well and removing the container therefrom and for selectively placing one of the first and second plugs in the top of the well. Neutron detectors are positioned within the neutron moderating material of the main body member around the sides of the well. At least one gamma ray detector is positioned adjacent the bottom of the well. A means receives and processes the signals from the neutron and gamma ray detectors when the container is in the well for determining the fissile and fertile material content of the incinerator residue in the container

  8. Neutron detector

    International Nuclear Information System (INIS)

    Endo, Hiroshi.

    1993-01-01

    The device of the present invention detects neutrons in a reactor container under a high temperature and reduces the noise level in an FBR type reactor. That is, the detection section comprises a high heat resistant vessel containing a scintillator therein for detecting neutrons. Neutron signals sent from the detection section are inputted to a neutron measuring section by way of a signal transmission section. The detection section is disposed at the inside of the reactor container. Further, the signal transmission section is connected optically to the detection section. With such a constitution, since the detection section comprising the high temperature resistant vessel is disposed at the inside of the reactor container, neutron fluxes can be detected and measured at high sensitivity even under a high temperature circumstance. Since the signal transmission section is optically connected to the detection section, influence of radiation rays upon transmission of the neutron detection signals can be reduced. Accordingly, the noise level can be kept low. (I.S.)

  9. Neutron Scattering

    International Nuclear Information System (INIS)

    Fayer, Michael J.; Gee, Glendon W.

    2005-01-01

    The neutron probe is a standard tool for measuring soil water content. This article provides an overview of the underlying theory, describes the methodology for its calibration and use, discusses example applications, and identifies the safety issues. Soil water makes land-based life possible by satisfying plant water requirements, serving as a medium for nutrient movement to plant roots and nutrient cycling, and controlling the fate and transport of contaminants in the soil environment. Therefore, a successful understanding of the dynamics of plant growth, nutrient cycling, and contaminant behavior in the soil requires knowledge of the soil water content as well as its spatial and temporal variability. After more than 50 years, neutron probes remain the most reliable tool available for field monitoring of soil water content. Neutron probes provide integrated measurements over relatively large volumes of soil and, with proper access, allow for repeated sampling of the subsurface at the same locations. The limitations of neutron probes include costly and time-consuming manual operation, lack of data automation, and costly regulatory requirements. As more non-radioactive systems for soil water monitoring are developed to provide automated profiling capabilities, neutron-probe usage will likely decrease. Until then, neutron probes will continue to be a standard for reliable measurements of field water contents in soils around the globe

  10. Study of atmospherical neutrinos therapeutic potential

    International Nuclear Information System (INIS)

    Roustit, Rudy

    2008-01-01

    Glioblastoma is nowadays one of the most murderer cancers with only 5 % survival after 3 years in case of classic treatment in radiotherapy. However, recently a new treatment have been create, the Boron Neutron Capture Therapy (BNCT) using interaction's properties between bore 10 atoms and low energy neutrons that produced by giant accelerators or nuclear reactors. The target of this stage consist in adapt this technique in using a natural neutron source (atmospheric neutrons) and to know his radio-biologic efficacy. For this, we have been realised a numerical simulation of this source throughout a patient's brain [fr

  11. Atmospheric contamination

    International Nuclear Information System (INIS)

    Gruetter, Juerg

    1997-01-01

    It is about the levels of contamination in center America, the population's perception on the problem, effects of the atmospheric contamination, effects in the environment, causes of the atmospheric contamination, possibilities to reduce the atmospheric contamination and list of Roeco Swisscontac in atmospheric contamination

  12. Neutron-neutron probe for uranium exploration

    International Nuclear Information System (INIS)

    Smith, R.C.

    1979-01-01

    A neutron activation probe for assaying the amount of fissionable isotopes in an ore body is described which comprises a casing which is movable through a borehole in the ore body, a neutron source and a number of delayed neutron detectors arranged colinearly in the casing below the neutron source for detecting delayed neutrons

  13. Neutron emission study after muon capture by nuclei

    International Nuclear Information System (INIS)

    Bouyssy, Alain.

    1974-01-01

    Muon capture by nuclei, used in the beginning for checking the weak interaction, is now a method of investigation of nuclear structure. Study of spectrum, asymmetry and polarization of emitted neutrons after polarized muon capture has been done in three directions: weak coupling constants, final state interaction, nuclear wave functions. The neutron intensity and helicity are very dependent of the neutron - residual nucleus interaction, while the asymmetry is sensitive to the wave functions used for the proton. Moreover if the induced tensor coupling constant is different from zero the asymmetry is increased. Longitudinal polarization experiments, with those for neutron intensity, would be of great interest to give informations on neutron asymmetry [fr

  14. Status of the Neutron Imaging and Diffraction Instrument IMAT

    Science.gov (United States)

    Kockelmann, Winfried; Burca, Genoveva; Kelleher, Joe F.; Kabra, Saurabh; Zhang, Shu-Yan; Rhodes, Nigel J.; Schooneveld, Erik M.; Sykora, Jeff; Pooley, Daniel E.; Nightingale, Jim B.; Aliotta, Francesco; Ponterio, Rosa C.; Salvato, Gabriele; Tresoldi, Dario; Vasi, Cirino; McPhate, Jason B.; Tremsin, Anton S.

    A cold neutron imaging and diffraction instrument, IMAT, is currently being constructed at the ISIS second target station. IMAT will capitalize on time-of-flight transmission and diffraction techniques available at a pulsed neutron source. Analytical techniques will include neutron radiography, neutron tomography, energy-selective neutron imaging, and spatially resolved diffraction scans for residual strain and texture determination. Commissioning of the instrument will start in 2015, with time-resolving imaging detectors and two diffraction detector prototype modules. IMAT will be operated as a user facility for material science applications and will be open for developments of time-of-flight imaging methods.

  15. Magnetic field devices for neutron spin transport and manipulation in precise neutron spin rotation measurements

    Energy Technology Data Exchange (ETDEWEB)

    Maldonado-Velázquez, M. [Posgrado en Ciencias Físicas, Universidad Nacional Autónoma de México, 04510 (Mexico); Barrón-Palos, L., E-mail: libertad@fisica.unam.mx [Instituto de Física, Universidad Nacional Autónoma de México, Apartado Postal 20-364, 01000 (Mexico); Crawford, C. [University of Kentucky, Lexington, KY 40506 (United States); Snow, W.M. [Indiana University, Bloomington, IN 47405 (United States)

    2017-05-11

    The neutron spin is a critical degree of freedom for many precision measurements using low-energy neutrons. Fundamental symmetries and interactions can be studied using polarized neutrons. Parity-violation (PV) in the hadronic weak interaction and the search for exotic forces that depend on the relative spin and velocity, are two questions of fundamental physics that can be studied via the neutron spin rotations that arise from the interaction of polarized cold neutrons and unpolarized matter. The Neutron Spin Rotation (NSR) collaboration developed a neutron polarimeter, capable of determining neutron spin rotations of the order of 10{sup −7} rad per meter of traversed material. This paper describes two key components of the NSR apparatus, responsible for the transport and manipulation of the spin of the neutrons before and after the target region, which is surrounded by magnetic shielding and where residual magnetic fields need to be below 100 μG. These magnetic field devices, called input and output coils, provide the magnetic field for adiabatic transport of the neutron spin in the regions outside the magnetic shielding while producing a sharp nonadiabatic transition of the neutron spin when entering/exiting the low-magnetic-field region. In addition, the coils are self contained, forcing the return magnetic flux into a compact region of space to minimize fringe fields outside. The design of the input and output coils is based on the magnetic scalar potential method.

  16. Prompt fission neutron spectra and average prompt neutron multiplicities

    International Nuclear Information System (INIS)

    Madland, D.G.; Nix, J.R.

    1983-01-01

    We present a new method for calculating the prompt fission neutron spectrum N(E) and average prompt neutron multiplicity anti nu/sub p/ as functions of the fissioning nucleus and its excitation energy. The method is based on standard nuclear evaporation theory and takes into account (1) the motion of the fission fragments, (2) the distribution of fission-fragment residual nuclear temperature, (3) the energy dependence of the cross section sigma/sub c/ for the inverse process of compound-nucleus formation, and (4) the possibility of multiple-chance fission. We use a triangular distribution in residual nuclear temperature based on the Fermi-gas model. This leads to closed expressions for N(E) and anti nu/sub p/ when sigma/sub c/ is assumed constant and readily computed quadratures when the energy dependence of sigma/sub c/ is determined from an optical model. Neutron spectra and average multiplicities calculated with an energy-dependent cross section agree well with experimental data for the neutron-induced fission of 235 U and the spontaneous fission of 252 Cf. For the latter case, there are some significant inconsistencies between the experimental spectra that need to be resolved. 29 references

  17. Aerial Neutron Detection: Neutron Signatures for Nonproliferation and Emergency Response Applications

    Energy Technology Data Exchange (ETDEWEB)

    Maurer, Richard J.; Stampahar, Thomas G.; Smith, Ethan X.; Mukhopadhyay, Sanjoy; Wolff, Ronald S.; Rourke, Timothy J.; LeDonne, Jeffrey P.; Avaro, Emanuele; Butler, D. Andre; Borders, Kevin L.; Stampahar, Jezabel; Schuck, William H.; Selfridge, Thomas L.; McKissack, Thomas M.; Duncan, William W.; Hendricks, Thane J.

    2012-10-17

    From 2007 to the present, the Remote Sensing Laboratory has been conducting a series of studies designed to expand our fundamental understanding of aerial neutron detection with the goal of designing an enhanced sensitivity detection system for long range neutron detection. Over 35 hours of aerial measurements in a helicopter were conducted for a variety of neutron emitters such as neutron point sources, a commercial nuclear power reactor, nuclear reactor spent fuel in dry cask storage, depleted uranium hexafluoride and depleted uranium metal. The goals of the project were to increase the detection sensitivity of our instruments such that a 5.4 × 104 neutron/second source could be detected at 100 feet above ground level at a speed of 70 knots and to enhance the long-range detection sensitivity for larger neutron sources, i.e., detection ranges above 1000 feet. In order to increase the sensitivity of aerial neutron detection instruments, it is important to understand the dynamics of the neutron background as a function of altitude. For aerial neutron detection, studies have shown that the neutron background primarily originates from above the aircraft, being produced in the upper atmosphere by galactic cosmic-ray interactions with air molecules. These interactions produce energetic neutrons and charged particles that cascade to the earth’s surface, producing additional neutrons in secondary collisions. Hence, the neutron background increases as a function of altitude which is an impediment to long-range neutron detection. In order to increase the sensitivity for long range detection, it is necessary to maintain a low neutron background as a function of altitude. Initial investigations show the variation in the neutron background can be decreased with the application of a cosmic-ray shield. The results of the studies along with a representative data set are presented.

  18. German neutron scattering conference. Programme and abstracts

    Energy Technology Data Exchange (ETDEWEB)

    Brueckel, Thomas (ed.)

    2012-07-01

    The German Neutron Scattering Conference 2012 - Deutsche Neutronenstreutagung DN 2012 offers a forum for the presentation and critical discussion of recent results obtained with neutron scattering and complementary techniques. The meeting is organized on behalf of the German Committee for Research with Neutrons - Komitee Forschung mit Neutronen KFN - by the Juelich Centre for Neutron Science JCNS of Forschungszentrum Juelich GmbH. In between the large European and international neutron scattering conferences ECNS (2011 in Prague) and ICNS (2013 in Edinburgh), it offers the vibrant German and international neutron community an opportunity to debate topical issues in a stimulating atmosphere. Originating from ''BMBF Verbundtreffen'' - meetings for projects funded by the German Federal Ministry of Education and Research - this conference series has a strong tradition of providing a forum for the discussion of collaborative research projects and future developments in the field of research with neutrons in general. Neutron scattering, by its very nature, is used as a powerful probe in many different disciplines and areas, from particle and condensed matter physics through to chemistry, biology, materials sciences, engineering sciences, right up to geology and cultural heritage; the German Neutron Scattering Conference thus provides a unique chance for exploring interdisciplinary research opportunities. It also serves as a showcase for recent method and instrument developments and to inform users of new advances at neutron facilities.

  19. German neutron scattering conference. Programme and abstracts

    International Nuclear Information System (INIS)

    Brueckel, Thomas

    2012-01-01

    The German Neutron Scattering Conference 2012 - Deutsche Neutronenstreutagung DN 2012 offers a forum for the presentation and critical discussion of recent results obtained with neutron scattering and complementary techniques. The meeting is organized on behalf of the German Committee for Research with Neutrons - Komitee Forschung mit Neutronen KFN - by the Juelich Centre for Neutron Science JCNS of Forschungszentrum Juelich GmbH. In between the large European and international neutron scattering conferences ECNS (2011 in Prague) and ICNS (2013 in Edinburgh), it offers the vibrant German and international neutron community an opportunity to debate topical issues in a stimulating atmosphere. Originating from ''BMBF Verbundtreffen'' - meetings for projects funded by the German Federal Ministry of Education and Research - this conference series has a strong tradition of providing a forum for the discussion of collaborative research projects and future developments in the field of research with neutrons in general. Neutron scattering, by its very nature, is used as a powerful probe in many different disciplines and areas, from particle and condensed matter physics through to chemistry, biology, materials sciences, engineering sciences, right up to geology and cultural heritage; the German Neutron Scattering Conference thus provides a unique chance for exploring interdisciplinary research opportunities. It also serves as a showcase for recent method and instrument developments and to inform users of new advances at neutron facilities.

  20. Fast neutron irradiation tests of flash memories used in space environment at the ISIS spallation neutron source

    Directory of Open Access Journals (Sweden)

    C. Andreani

    2018-02-01

    Full Text Available This paper presents a neutron accelerated study of soft errors in advanced electronic devices used in space missions, i.e. Flash memories performed at the ChipIr and VESUVIO beam lines at the ISIS spallation neutron source. The two neutron beam lines are set up to mimic the space environment spectra and allow neutron irradiation tests on Flash memories in the neutron energy range above 10 MeV and up to 800 MeV. The ISIS neutron energy spectrum is similar to the one occurring in the atmospheric as well as in space and planetary environments, with intensity enhancements varying in the range 108- 10 9 and 106- 10 7 respectively. Such conditions are suitable for the characterization of the atmospheric, space and planetary neutron radiation environments, and are directly applicable for accelerated tests of electronic components as demonstrated here in benchmark measurements performed on flash memories.

  1. Fast neutron irradiation tests of flash memories used in space environment at the ISIS spallation neutron source

    Science.gov (United States)

    Andreani, C.; Senesi, R.; Paccagnella, A.; Bagatin, M.; Gerardin, S.; Cazzaniga, C.; Frost, C. D.; Picozza, P.; Gorini, G.; Mancini, R.; Sarno, M.

    2018-02-01

    This paper presents a neutron accelerated study of soft errors in advanced electronic devices used in space missions, i.e. Flash memories performed at the ChipIr and VESUVIO beam lines at the ISIS spallation neutron source. The two neutron beam lines are set up to mimic the space environment spectra and allow neutron irradiation tests on Flash memories in the neutron energy range above 10 MeV and up to 800 MeV. The ISIS neutron energy spectrum is similar to the one occurring in the atmospheric as well as in space and planetary environments, with intensity enhancements varying in the range 108- 10 9 and 106- 10 7 respectively. Such conditions are suitable for the characterization of the atmospheric, space and planetary neutron radiation environments, and are directly applicable for accelerated tests of electronic components as demonstrated here in benchmark measurements performed on flash memories.

  2. neutron radiography

    International Nuclear Information System (INIS)

    Barton, J.P.

    1993-01-01

    Neutron radiography (or radiology) is a diverse filed that uses neutrons of various energies, subthermal, thermal, epithermal or fast in either steady state or pulsed mode to examine objects for industrial, medical, or other purposes, both microscopic and macroscopic. The applications include engineering design, biological studies, nondestructive inspection and materials evaluation. In the past decade, over 100 different centers in some 30 countries have published reports of pioneering activities using reactors, accelerators and isotopic neutron sources. While film transparency and electronic video are most common imaging methods for static or in motion objects respectively, there are other important data gathering techniques, including track etch, digital gauging and computed tomography. A survey of the world-wide progress shows the field to be gaining steadily in its diversity, its sophistication and its importance. (author)

  3. NEUTRONIC REACTOR

    Science.gov (United States)

    Wigner, E.P.; Weinberg, A.W.; Young, G.J.

    1958-04-15

    A nuclear reactor which uses uranium in the form of elongated tubes as fuel elements and liquid as a coolant is described. Elongated tubular uranium bodies are vertically disposed in an efficient neutron slowing agent, such as graphite, for example, to form a lattice structure which is disposed between upper and lower coolant tanks. Fluid coolant tubes extend through the uranium bodies and communicate with the upper and lower tanks and serve to convey the coolant through the uranium body. The reactor is also provided with means for circulating the cooling fluid through the coolant tanks and coolant tubes, suitable neutron and gnmma ray shields, and control means.

  4. Neutron dosimeter

    International Nuclear Information System (INIS)

    Bartko, J.; Schoch, K.F. Jr.; Congedo, T.V.; Anderson, S.L. Jr.

    1989-01-01

    This patent describes a nuclear reactor. It comprises a reactor core; a thermal shield surrounding the reactor core; a pressure vessel surrounding the thermal shield; a neutron dosimeter positioned outside of the thermal shield, the neutron dosimeter comprising a layer of fissile material and a second layer made of a material having an electrical conductivity which permanently varies as a function of its cumulative ion radiation dose; and means, outside the pressure vessel and electrically connected to the layer of second material, for measuring electrical conductivity of the layer of second material

  5. Quantitative neutron radiography using neutron absorbing honeycomb

    International Nuclear Information System (INIS)

    Tamaki, Masayoshi; Oda, Masahiro; Takahashi, Kenji; Ohkubo, Kohei; Tasaka, Kanji; Tsuruno, Akira; Matsubayashi, Masahito.

    1993-01-01

    This investigation concerns quantitative neutron radiography and computed tomography by using a neutron absorbing honeycomb collimator. By setting the neutron absorbing honeycomb collimator between object and imaging system, neutrons scattered in the object were absorbed by the honeycomb material and eliminated before coming to the imaging system, but the neutrons which were transmitted the object without interaction could reach the imaging system. The image by purely transmitted neutrons gives the quantitative information. Two honeycombs were prepared with coating of boron nitride and gadolinium oxide and evaluated for the quantitative application. The relation between the neutron total cross section and the attenuation coefficient confirmed that they were in a fairly good agreement. Application to quantitative computed tomography was also successfully conducted. The new neutron radiography method using the neutron-absorbing honeycomb collimator for the elimination of the scattered neutrons improved remarkably the quantitativeness of the neutron radiography and computed tomography. (author)

  6. Neutronics of pulsed spallation neutron sources

    CERN Document Server

    Watanabe, N

    2003-01-01

    Various topics and issues on the neutronics of pulsed spallation neutron sources, mainly for neutron scattering experiments, are reviewed to give a wide circle of readers a better understanding of these sources in order to achieve a high neutronic performance. Starting from what neutrons are needed, what the spallation reaction is and how to produce slow-neutrons more efficiently, the outline of the target and moderator neutronics are explained. Various efforts with some new concepts or ideas have already been devoted to obtaining the highest possible slow-neutron intensity with desired pulse characteristics. This paper also reviews the recent progress of such efforts, mainly focused on moderator neutronics, since moderators are the final devices of a neutron source, which determine the source performance. Various governing parameters for neutron-pulse characteristics such as material issues, geometrical parameters (shape and dimensions), the target-moderator coupling scheme, the ortho-para-hydrogen ratio, po...

  7. Pesticide residues in locally available cereals and vegetables

    International Nuclear Information System (INIS)

    Cunanan, S.A.; Santos, F.L.; Bonoan, L.S.

    1976-03-01

    Vegetable samples (pechay, cabbage, lettuce, green beans and tomatoes) bought from public markets in the Metro Manila area were analyzed for pesticide residues using gas chromatography. The samples analyzed in 1968-69 contained high levels of chlorinated pesticides such as DDT, Aldrin, Endrin, and Thiodan, while in the samples analyzed in January 1976, no chlorinated and organophosphate pesticides were detected. Cereal samples (rice, corn and sorghum) were obtained from the National Grains Authority and analyzed for pesticide residues and bromine residues. Total bromine residues was determined by neutron activation analysis. In most of the samples analyzed, the concentrations of pesticide residues were below the tolerance levels set by the FAO/WHO Committee on Pesticide Residues in Foods. An exception was one rice sample from Thailand, the bromine residue content (110ppm) of which exceeds the tolerance level of 50ppm

  8. Cosmic-ray neutron simulations and measurements in Taiwan

    International Nuclear Information System (INIS)

    Chen, Wei-Lin; Jiang, Shiang-Huei; Sheu, Rong-Jiun

    2014-01-01

    This study used simulations of galactic cosmic ray in the atmosphere to investigate the neutron background environment in Taiwan, emphasising its altitude dependence and spectrum variation near interfaces. The calculated results were analysed and compared with two measurements. The first measurement was a mobile neutron survey from sea level up to 3275 m in altitude conducted using a car-mounted high-sensitivity neutron detector. The second was a previous measured result focusing on the changes in neutron spectra near air/ground and air/water interfaces. The attenuation length of cosmic-ray neutrons in the lower atmosphere was estimated to be 163 g cm -2 in Taiwan. Cosmic-ray neutron spectra vary with altitude and especially near interfaces. The determined spectra near the air/ground and air/water interfaces agree well with measurements for neutrons below 10 MeV. However, the high-energy portion of spectra was observed to be much higher than our previous estimation. Because high-energy neutrons contribute substantially to a dose evaluation, revising the annual sea-level effective dose from cosmic-ray neutrons at ground level in Taiwan to 35 μSv, which corresponds to a neutron flux of 5.30 x 10 -3 n cm -2 s -1 , was suggested. The cosmic-ray neutron background in Taiwan was studied using the FLUKA simulations and field measurements. A new measurement was performed using a car-mounted high-efficiency neutron detector, re-coding real-time neutron counting rates from sea level up to 3275 m. The attenuation of cosmic-ray neutrons in the lower atmosphere exhibited an effective attenuation length of 163 g cm -2 . The calculated neutron counting rates over predicted the measurements by ∼32 %, which leaded to a correction factor for the FLUKA-calculated cosmic-ray neutrons in the lower atmosphere in Taiwan. In addition, a previous measurement regarding neutron spectrum variation near the air/ground and air/water interfaces was re-evaluated. The results showed that the

  9. Neutronic reactor

    International Nuclear Information System (INIS)

    Wende, C.W.J.

    1976-01-01

    The method of operating a water-cooled neutronic reactor having a graphite moderator is described which comprises flowing a gaseous mixture of carbon dioxide and helium, in which the helium comprises 40--60 volume percent of the mixture, in contact with the graphite moderator. 2 claims, 4 figures

  10. Neutron reflectivity

    Directory of Open Access Journals (Sweden)

    Cousin Fabrice

    2015-01-01

    Full Text Available The specular neutron reflectivity is a technique enabling the measurement of neutron scattering length density profile perpendicular to the plane of a surface or an interface, and thereby the profile of chemical composition. The characteristic sizes that are probed range from around 5 Å up 5000 Å. It is a scattering technique that averages information on the entire surface and it is therefore not possible to obtain information within the plane of the interface. The specific properties of neutrons (possibility of tuning the contrast by isotopic substitution, sensitivity to magnetism, negligible absorption, low energy of the incident neutrons makes it particularly interesting in the fields of soft matter, biophysics and magnetic thin films. This course is a basic introduction to the technique and does not address the magnetic reflectivity. It is composed of three parts describing respectively its principle and its formalism, the experimental aspects of the method (spectrometers, samples and two examples related to the materials for energy.

  11. Workshop on industrial application of neutron diffraction. Stress measurement by neutron diffraction

    CERN Document Server

    Minakawa, N; Morii, Y; Oyama, Y

    2002-01-01

    This workshop was planned to make use of the neutron from the reactor and the pulse neutron source JSNS for the industrial world. Especially, this workshop focused on the stress measurement by the neutron diffraction and it was held on the Tokai JAERI from October 15 to 16, 2001. The participant total was 93 and 40 participated from the industrial world. The introduction of the residual stress development of measurement technique by the neutron diffraction method and a research of the measurement of the residual stress such as the nuclear reactor material, the ordinary structure material, the composite material, the quenching steel, the high strength material were presented and discussed in this workshop. Moreover, it was introduced for the industrial world that an internal stress measurement is important for development of new product or an improvement of a manufacturing process. The question from the industrial world about which can be measured the product form, the size, the measurement precision, the reso...

  12. Methods for absorbing neutrons

    Science.gov (United States)

    Guillen, Donna P [Idaho Falls, ID; Longhurst, Glen R [Idaho Falls, ID; Porter, Douglas L [Idaho Falls, ID; Parry, James R [Idaho Falls, ID

    2012-07-24

    A conduction cooled neutron absorber may include a metal matrix composite that comprises a metal having a thermal neutron cross-section of at least about 50 barns and a metal having a thermal conductivity of at least about 1 W/cmK. Apparatus for providing a neutron flux having a high fast-to-thermal neutron ratio may include a source of neutrons that produces fast neutrons and thermal neutrons. A neutron absorber positioned adjacent the neutron source absorbs at least some of the thermal neutrons so that a region adjacent the neutron absorber has a fast-to-thermal neutron ratio of at least about 15. A coolant in thermal contact with the neutron absorber removes heat from the neutron absorber.

  13. Neutron stars as cosmic neutron matter laboratories

    International Nuclear Information System (INIS)

    Pines, D.

    1986-01-01

    Recent developments which have radically changed our understanding of the dynamics of neutron star superfluids and the free precession of neutron stars are summarized, and the extent to which neutron stars are cosmic neutron matter laboratories is discussed. 17 refs., 1 tab

  14. Basic of Neutron NDA

    Energy Technology Data Exchange (ETDEWEB)

    Trahan, Alexis Chanel [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-09-15

    The objectives of this presentation are to introduce the basic physics of neutron production, interactions and detection; identify the processes that generate neutrons; explain the most common neutron mechanism, spontaneous and induced fission and (a,n) reactions; describe the properties of neutron from different sources; recognize advantages of neutron measurements techniques; recognize common neutrons interactions; explain neutron cross section measurements; describe the fundamental of 3He detector function and designs; and differentiate between passive and active assay techniques.

  15. Internal exposure to neutron-activated {sup 56}Mn dioxide powder in Wistar rats. Pt. 1. Dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Stepanenko, Valeriy; Kaprin, Andrey; Galkin, Vsevolod; Ivanov, Sergey; Kolyzhenkov, Timofey; Petukhov, Aleksey; Yaskova, Elena; Belukha, Irina; Khailov, Artem; Skvortsov, Valeriy; Ivannikov, Alexander; Akhmedova, Umukusum; Bogacheva, Viktoria [Medical Radiological Research Center (MRRC) named after A.F. Tsyb - National Medical Research Radiological Center of the Health Ministry of the Russian Federation, Obninsk, Kaluga Region (Russian Federation); Rakhypbekov, Tolebay; Dyussupov, Altay; Chaizhunusova, Nailya; Sayakenov, Nurlan; Uzbekov, Darkhan; Saimova, Aisulu; Shabdarbaeva, Dariya; Kairkhanova, Yankar [Semey State Medical University, Semey (Kazakhstan); Otani, Keiko; Endo, Satoru; Satoh, Kenichi; Kawano, Noriyuki; Fujimoto, Nariaki; Hoshi, Masaharu [Hiroshima University, Hiroshima (Japan); Shichijo, Kazuko; Nakashima, Masahiro; Takatsuji, Toshihiro [Nagasaki University, Nagasaki (Japan); Sakaguchi, Aya; Kato, Hiroaki; Onda, Yuichi [University of Tsukuba, Ibaraki (Japan); Toyoda, Shin [Okayama University of Science, Okayama (Japan); Sato, Hitoshi [Ibaraki Prefectural University of Health Science, Ibaraki (Japan); Skakov, Mazhin; Vurim, Alexandr; Gnyrya, Vyacheslav; Azimkhanov, Almas; Kolbayenkov, Alexander [National Nuclear Center of the Republic of Kazakhstan, Kurchatov (Kazakhstan); Zhumadilov, Kasym [Eurasian National University named after L.N. Gumilyov, Astana (Kazakhstan)

    2017-03-15

    There were two sources of ionizing irradiation after the atomic bombings of Hiroshima and Nagasaki: (1) initial gamma-neutron irradiation at the moment of detonation and (2) residual radioactivity. Residual radioactivity consisted of two components: radioactive fallout containing fission products, including radioactive fissile materials from nuclear device, and neutron-activated radioisotopes from materials on the ground. The dosimetry systems DS86 and DS02 were mainly devoted to the assessment of initial radiation exposure to neutrons and gamma rays, while only brief considerations were given for the estimation of doses caused by residual radiation exposure. Currently, estimation of internal exposure of atomic bomb survivors due to dispersed radioactivity and neutron-activated radioisotopes from materials on the ground is a matter of some interest, in Japan. The main neutron-activated radionuclides in soil dust were {sup 24}Na, {sup 28}Al, {sup 31}Si, {sup 32}P, {sup 38}Cl, {sup 42}K, {sup 45}Ca, {sup 46}Sc, {sup 56}Mn, {sup 59}Fe, {sup 60}Co, and {sup 134}Cs. The radionuclide {sup 56}Mn (T{sub 1/2} = 2.58 h) is known as one of the dominant beta- and gamma emitters during the first few hours after neutron irradiation of soil and other materials on ground, dispersed in the form of dust after a nuclear explosion in the atmosphere. To investigate the peculiarities of biological effects of internal exposure to {sup 56}Mn in comparison with external gamma irradiation, a dedicated experiment with Wistar rats exposed to neutron-activated {sup 56}Mn dioxide powder was performed recently by Shichijo and coworkers. The dosimetry required for this experiment is described here. Assessment of internal radiation doses was performed on the basis of measured {sup 56}Mn activity in the organs and tissues of the rats and of absorbed fractions of internal exposure to photons and electrons calculated with the MCNP-4C Monte Carlo using a mathematical rat phantom. The first results of

  16. Statistical theory of neutron nuclear reactions

    International Nuclear Information System (INIS)

    Moldauer, P.A.

    1980-01-01

    The statistical theory of average neutron nucleus reaction cross sections is reviewed with emphasis on the justification of the Hauser Feshbach formula and its modifications for situations including isolated compound nucleus resonances, overlapping and interfering resonances, the competition of compound and direct reactions, and continuous treatment of residual nuclear states. (author)

  17. Statistical theory of neutron nuclear reactions

    International Nuclear Information System (INIS)

    Moldauer, P.A.

    1978-02-01

    The statistical theory of average neutron nucleus reaction cross sections is reviewed with emphasis on the justification of the Hauser Feshbach formula and its modifications for situations including isolated compound nucleus resonances, overlapping and interfering resonances, the competition of compound and direct reactions, and continuous treatment of residual nuclear states

  18. Statistical theory of neutron nuclear reactions

    International Nuclear Information System (INIS)

    Moldauer, P.A.

    1975-01-01

    The statistical theory of average neutron nucleus reaction cross sections is reviewed with emphasis on the justification of the Hauser Feshbach formula and its modifications for situations including isolated compound nucleus resonances, overlapping and interfering resonances, the competition of compound and direct reactions, and continuous treatment of residual nuclear states. 3 figures

  19. Hydrodynamics of oceans and atmospheres

    CERN Document Server

    Eckart, Carl

    1960-01-01

    Hydrodynamics of Oceans and Atmospheres is a systematic account of the hydrodynamics of oceans and atmospheres. Topics covered range from the thermodynamic functions of an ideal gas and the thermodynamic coefficients for water to steady motions, the isothermal atmosphere, the thermocline, and the thermosphere. Perturbation equations, field equations, residual equations, and a general theory of rays are also presented. This book is comprised of 17 chapters and begins with an introduction to the basic equations and their solutions, with the aim of illustrating the laws of dynamics. The nonlinear

  20. Neutron scattering. Lectures

    International Nuclear Information System (INIS)

    Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner

    2013-01-01

    The following topics are dealt with: Neutron sources, symmetry of crystals, nanostructures investigated by small-angle neutron scattering, structure of macromolecules, spin dependent and magnetic scattering, structural analysis, neutron reflectometry, magnetic nanostructures, inelastic neutron scattering, strongly correlated electrons, polymer dynamics, applications of neutron scattering. (HSI)

  1. Neutron scattering. Lectures

    International Nuclear Information System (INIS)

    Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner

    2012-01-01

    The following topics are dealt with: Neutron scattering in contemporary research, neutron sources, symmetry of crystals, diffraction, nanostructures investigated by small-angle neutron scattering, the structure of macromolecules, spin dependent and magnetic scattering, structural analysis, neutron reflectometry, magnetic nanostructures, inelastic scattering, strongly correlated electrons, dynamics of macromolecules, applications of neutron scattering. (HSI)

  2. Pulsed neutron generator

    International Nuclear Information System (INIS)

    Bespalov, D.F.; Bykovskii, Yu.A.; Vergun, I.I.; Kozlovskii, K.I.; Kozyrev, Yu.P.; Leonov, R.K.; Simagin, B.I.; Tsybin, A.S.; Shikanov, A.Ie.

    1986-03-01

    The paper describes a new device for generating pulsed neutron fields, utilized in nuclear geophysics for carrying out pulsed neutron logging and activation analysis under field conditions. The invention employs a sealed-off neutron tube with a laser ion source which increases neutron yield to the level of 10 neutrons per second or higher. 2 refs., 1 fig

  3. Residual strains in girth-welded linepipe

    International Nuclear Information System (INIS)

    MacEwen, S.R.; Holden, T.M.; Powell, B.M.; Lazor, R.B.

    1987-07-01

    High resolution neutron diffraction has been used to measure the axial residual strains in and adjacent to a multipass girth weld in a complete section of 914 mm (36 inches) diameter, 16 mm (5/8 inch) wall, linepipe. The experiments were carried out at the NRU reactor, Chalk River using the L3 triple-axis spectrometer. The through-wall distribution of axial residual strain was measured at 0, 4, 8, 20 and 50 mm from the weld centerline; the axial variation was determined 1, 5, 8, and 13 mm from the inside surface of the pipe wall. The results have been compared with strain gauge measurements on the weld surface and with through-wall residual stress distributions determined using the block-layering and removal technique

  4. Neutron scattering

    International Nuclear Information System (INIS)

    1991-02-01

    The annual report on hand gives an overview of the research work carried out in the Laboratory for Neutron Scattering (LNS) of the ETH Zuerich in 1990. Using the method of neutron scattering, it is possible to examine in detail the static and dynamic properties of the condensed material. In accordance with the multidisciplined character of the method, the LNS has for years maintained a system of intensive co-operation with numerous institutes in the areas of biology, chemistry, solid-state physics, crystallography and materials research. In 1990 over 100 scientists from more than 40 research groups both at home and abroad took part in the experiments. It was again a pleasure to see the number of graduate students present, who were studying for a doctorate and who could be introduced into the neutron scattering during their stay at the LNS and thus were in the position to touch on central ways of looking at a problem in their dissertation using this modern experimental method of solid-state research. In addition to the numerous and interesting ways of formulating the questions to explain the structure, nowadays the scientific programme increasingly includes particularly topical studies in connection with high temperature-supraconductors and materials research

  5. Neutron radiotherapy

    International Nuclear Information System (INIS)

    Thomas, F.J.

    1987-01-01

    The rationale for the application of neutron radiation for the treatment of malignancies is well established based on radiobiological studies. These factors include the presence of tissue hypoxia, radiation response as a function of cell cycle kinetics, the repair capacity of the malignant cells and the regeneration of malignant cells during a fractionated course of radiation. Despite the constraints under which the clinical trials to date have been conducted, promising results have been obtained. Randomized trials have demonstrated that neutron therapy is the treatment of choice for inoperable salivary gland carcinomas. A randomized trial of the RTOG has demonstrated a probable advantage for neutron radiation in the treatment of advanced prostate carcinomas but is yet to be confirmed. An improvement in local control has also been observed for selected sarcomas. Equivocal or contradictory results have been obtained for squamous cell carcinomas of the head and neck, bronchogenic carcinomas, advanced rectal, transitional cell carcinomas of the bladder and cervical carcinomas. The practical consequences of these radiobiological and clinical observations on the current generation of clinical trials is discussed

  6. Pluto's atmosphere

    International Nuclear Information System (INIS)

    Elliot, J.L.; Dunham, E.W.; Bosh, A.S.; Slivan, S.M.; Young, L.A.

    1989-01-01

    Airborne CCD photometer observations of Pluto's June 9, 1988 stellar occultation have yielded an occultation lightcurve, probing two regions on the sunrise limb 2000 km apart, which reveals an upper atmosphere overlying an extinction layer with an abrupt upper boundary. The extinction layer may surround the entire planet. Attention is given to a model atmosphere whose occultation lightcurve closely duplicates observations; fits of the model to the immersion and emersion lightcurves exhibit no significant derived atmosphere-structure differences. Assuming a pure methane atmosphere, surface pressures of the order of 3 microbars are consistent with the occultation data. 43 references

  7. Atmospheric electricity

    CERN Document Server

    Chalmers, J Alan

    1957-01-01

    Atmospheric Electricity brings together numerous studies on various aspects of atmospheric electricity. This book is composed of 13 chapters that cover the main problems in the field, including the maintenance of the negative charge on the earth and the origin of the charges in thunderstorms. After a brief overview of the historical developments of atmospheric electricity, this book goes on dealing with the general principles, results, methods, and the MKS system of the field. The succeeding chapters are devoted to some aspects of electricity in the atmosphere, such as the occurrence and d

  8. A neutron detector for measurement of total neutron production cross sections

    Energy Technology Data Exchange (ETDEWEB)

    Sekharan, K K; Laumer, H; Kern, B D; Gabbard, F [Kentucky Univ., Lexington (USA). Dept. of Physics and Astronomy

    1976-03-01

    A neutron detector has been constructed and calibrated for the accurate measurement of total neutron production cross sections. The detector consists of a polyethylene sphere of 60 cm diameter in which eight /sup 10/BF/sub 3/ counters have been installed radially. The relative efficiency of this detector has been determined for average neutron energies from 30 keV to 1.5 MeV by counting neutrons from /sup 7/Li(p, n)/sup 7/Be. By adjusting the radial positions of the BF/sub 3/ counters in the polyethylene sphere the efficiency for neutron detection was made nearly constant for this energy range. Measurement of absolute efficiency for the same neutron energy range has been done by counting the neutrons from /sup 51/V(p, n)/sup 51/Cr and /sup 57/Fe(p, n)/sup 57/Co reactions and determining the absolute number of residual nuclei produced during the measurement of neutron yield. Details of absolute efficiency measurements and the use of the detector for determination of neutron production cross sections are given.

  9. A neutron detector for measurement of total neutron production cross sections

    International Nuclear Information System (INIS)

    Sekharan, K.K.; Laumer, H.; Kern, B.D.; Gabbard, F.

    1976-01-01

    A neutron detector has been constructed and calibrated for the accurate measurement of total neutron production cross sections. The detector consists of a polyethylene sphere of 60 cm diameter in which eight 10 BF 3 counters have been installed radially. The relative efficiency of this detector has been determined for average neutron energies from 30 keV to 1.5 MeV by counting neutrons from 7 Li(p, n) 7 Be. By adjusting the radial positions of the BF 3 counters in the polyethylene sphere the efficiency for neutron detection was made nearly constant for this energy range. Measurement of absolute efficiency for the same neutron energy range has been done by counting the neutrons from 51 V(p, n) 51 Cr and 57 Fe(p, n) 57 Co reactions and determining the absolute number of residual nuclei produced during the measurement of neutron yield. Details of absolute efficiency measurements and the use of the detector for determination of neutron production cross sections are given. (Auth.)

  10. Special Features of the Air to Space Neutron Transport Problem

    Science.gov (United States)

    2017-09-14

    an atmosphere model. Radioactive Decay Free neutrons are not stable elementary particles. They decay radioactively with a half- life of around ten...milliseconds to seconds, so that radioactive decay of neutrons is negligible. (The probability of decay in 100 milliseconds with a 10 minute half- life is...the bottom and top of a layer are 1bZ - and bZ respectively. The methods developed here apply to any planet with an atmosphere and an orbiting

  11. Toxic metals in the atmosphere

    International Nuclear Information System (INIS)

    Munoz-Ribadeneira, F.J.; Mo, T.; Canoy, M.J.

    1975-05-01

    Methods used in Puerto Rico for monitoring toxic metals in the atmosphere are described. Air sampling machines are placed at heights from 15 to 25 ft above the surface and the tapes are subjected to neutron activation and γ spectroscopy. The concentrations of up to 33 elements can be determined with precision and sensitivity without destroying the tapes, which can then be used for analysis by other methods. (U.S.)

  12. Spallation Neutron Source (SNS)

    Data.gov (United States)

    Federal Laboratory Consortium — The SNS at Oak Ridge National Laboratory is a next-generation spallation neutron source for neutron scattering that is currently the most powerful neutron source in...

  13. Articulating Atmospheres

    DEFF Research Database (Denmark)

    Kinch, Sofie

    2011-01-01

    This paper presents an architectural approach to designing computational interfaces by articulating the notion of atmosphere in the field of interaction design. It draws upon the concept of kinesthetic interaction and a philosophical notion on atmosphere emphasizing the importance of bodily...

  14. Atmospheric electrodynamics

    International Nuclear Information System (INIS)

    Volland, H.

    1984-01-01

    The book Atmospheric Electrodynamics, by Hans Voland is reviewed. The book describes a wide variety of electrical phenomena occurring in the upper and lower atmosphere and develops the mathematical models which simulate these processes. The reviewer finds that the book is of interest to researchers with a background in electromagnetic theory but is of only limited use as a reference work

  15. Solid-phase extraction combined with high-performance liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry analysis of pesticides in water: method performance and application in a reconnaissance survey of residues in drinking water in Greater Cairo, Egypt.

    Science.gov (United States)

    Potter, Thomas L; Mohamed, Mahmoud A; Ali, Hannah

    2007-01-24

    Monitoring of water resources for pesticide residues is often needed to ensure that pesticide use does not adversely impact the quality of public water supplies or the environment. In many rural areas and throughout much of the developing world, monitoring is often constrained by lack of testing facilities; thus, collection of samples and shipment to centralized laboratories for analysis is required. The portability, ease of use, and potential to enhance analyte stability make solid-phase extraction (SPE) an attractive technique for handling water samples prior to their shipment. We describe performance of an SPE method targeting a structurally diverse mixture of 25 current-use pesticides and two common degradates in samples of raw and filtered drinking water collected in Greater Cairo, Egypt. SPE was completed in a field laboratory in Egypt, and cartridges were shipped to the United States for elution and high-performance liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry analysis. Quantitative and reproducible recovery of 23 of 27 compounds (average = 96%; percent relative standard deviation = 21%) from matrix spikes (1 microg L-1 per component) prepared in the field and from deionized water fortified similarly in the analytical laboratory was obtained. Concurrent analysis of unspiked samples identified four parent compounds and one degradate in drinking water samples. No significant differences were observed between raw and filtered samples. Residue levels in all cases were below drinking water and "harm to aquatic-life" thresholds, indicating that human and ecological risks of pesticide contamination were relatively small; however, the study was limited in scale and scope. Further monitoring is needed to define spatial and temporal variation in residue concentrations. The study has demonstrated the feasibility of performing studies of this type using SPE to extract and preserve samples in the field. The approach should be broadly

  16. Urban atmospheres.

    Science.gov (United States)

    Gandy, Matthew

    2017-07-01

    What is an urban atmosphere? How can we differentiate an 'atmosphere' from other facets of urban consciousness and experience? This essay explores some of the wider cultural, political, and philosophical connotations of atmospheres as a focal point for critical reflections on space and subjectivity. The idea of an 'affective atmosphere' as a distinctive kind of mood or shared corporeal phenomenon is considered in relation to recent developments in phenomenology, extended conceptions of agency, and new understandings of materialism. The essay draws in particular on the changing characteristics of air and light to reflect on different forms of sensory experience and their wider cultural and political connotations. The argument highlights some of the tensions and anomalies that permeate contemporary understandings of urban atmospheres.

  17. A utilização da difração de neutrões na determinação do perfil de tensões residuais em revestimentos por soldadura The use of neutron diffraction for the determination of the in-depth residual stresses profile in weld coatings

    Directory of Open Access Journals (Sweden)

    Maria José Marques

    2013-06-01

    Full Text Available A técnica de difração de neutrões é usada neste artigo para estudar amostras ferríticas, revestidas comaços inoxidáveisausteníticos através de soldadura por arco submerso. Este procedimento é frequentemente usado no fabrico de equipamentos de processo para as indústrias química e nuclear, por facilidade de execução e razões económicas. A principal desvantagem deste processo de revestimento é a fissuração que frequentemente ocorre na interface material base/soldadura, potenciada pela presença de tensões residuais resultantes da operação de soldadura, a qual pode ser minimizada com a realização de tratamentos térmicos de relaxação de tensões. As amostras foram produzidas a partir de placas em aço ao carbono, tendo uma das superfícies sido revestida com dois tipos de aço inoxidável. Para a primeira camada foi usado um elétrodo EN 12072 - S 23 12 2 L e para a segunda e a terceira camadas foi usado um elétrodo EN 12072 - S 19 12 3 L. Após a soldadura, as amostras foram submetidas a um tratamento térmico de relaxação de tensões, durante 1 hora, à temperatura de 620ºC. Os perfis de tensões residuais obtidos por difração de neutrões evidenciam a relaxação de tensões residuais após o tratamento térmico realizado. A técnica de difração de neutrões revelou-se muito adequada na avaliação de tensões residuais neste tipo de ligações.The neutron diffraction is a non-destructive technique, particularly suitable for the analysis of residual stress fields in welds. The technique is used in this article to study ferritic samples, coated by submerged arc welding using stainless steel filler metals. This procedure is often used for manufacturing process equipment for chemical and nuclear industries, for ease of implementation and economic reasons. The main disadvantage of that processes is the cracking phenomenon that often occurs at the interface between the base material and coatings, which can be

  18. High energy neutron radiography

    International Nuclear Information System (INIS)

    Gavron, A.; Morley, K.; Morris, C.; Seestrom, S.; Ullmann, J.; Yates, G.; Zumbro, J.

    1996-01-01

    High-energy spallation neutron sources are now being considered in the US and elsewhere as a replacement for neutron beams produced by reactors. High-energy and high intensity neutron beams, produced by unmoderated spallation sources, open potential new vistas of neutron radiography. The authors discuss the basic advantages and disadvantages of high-energy neutron radiography, and consider some experimental results obtained at the Weapons Neutron Research (WNR) facility at Los Alamos

  19. Neutron scattering. Lectures

    Energy Technology Data Exchange (ETDEWEB)

    Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner (eds.)

    2010-07-01

    The following topics are dealt with: Neutron sources, neutron properties and elastic scattering, correlation functions measured by scattering experiments, symmetry of crystals, applications of neutron scattering, polarized-neutron scattering and polarization analysis, structural analysis, magnetic and lattice excitation studied by inelastic neutron scattering, macromolecules and self-assembly, dynamics of macromolecules, correlated electrons in complex transition-metal oxides, surfaces, interfaces, and thin films investigated by neutron reflectometry, nanomagnetism. (HSI)

  20. Neutron scattering. Lectures

    International Nuclear Information System (INIS)

    Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner

    2010-01-01

    The following topics are dealt with: Neutron sources, neutron properties and elastic scattering, correlation functions measured by scattering experiments, symmetry of crystals, applications of neutron scattering, polarized-neutron scattering and polarization analysis, structural analysis, magnetic and lattice excitation studied by inelastic neutron scattering, macromolecules and self-assembly, dynamics of macromolecules, correlated electrons in complex transition-metal oxides, surfaces, interfaces, and thin films investigated by neutron reflectometry, nanomagnetism. (HSI)

  1. Optimization of bent perfect Si(220)-crystal monochromator for residual strain/stress instrument - Part II

    Czech Academy of Sciences Publication Activity Database

    Moon, MK.; Em, Vt.; Lee, C.H.; Mikula, Pavol; Hong, KP; Choi, YH; Cheon, JK; Nam, UW; Kong, KN; Jin, KC

    2005-01-01

    Roč. 368, 1 2 3 4 (2005), s. 70-75 ISSN 0921-4526 R&D Projects: GA ČR(CZ) GA202/03/0891 Institutional research plan: CEZ:AV0Z10480505 Keywords : neutron monochromator * residual stress measurement * neutron diffractometers Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.796, year: 2005

  2. Neutron absorbing element

    International Nuclear Information System (INIS)

    Kasai, Shigeo.

    1991-01-01

    The present invention concerns a neutron absorbing element of a neutron shielding member used for an LMFBR type reactor. The inside of a fuel can sealed at both of the upper and the lower ends thereof with plugs is partitioned into an upper and a lower chambers by an intermediate plug. A discharging hole is disposed at the upper end plug, which is in communication with the outside. A communication tube is disposed at the intermediate end plug and it is in communication with the lower chamber containing B 4 C pellets. A cylindrical support member having three porous plugs connected in series is disposed at the lower surface of the discharging hole provided at the upper end plug. Further, the end of the discharging hole is sealed with high temperature solder and He atmosphere is present at the inside of the fuel can. With such a constitution, the supporting differential pressure of the porous plugs can be made greater while discharging He gases generated from B 4 C to the outside. Further, the porous plugs can be surely wetted by coolants. Accordingly, it is possible to increase life time and shorten the size. (I.N.)

  3. Neutron Therapy Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Neutron Therapy Facility provides a moderate intensity, broad energy spectrum neutron beam that can be used for short term irradiations for radiobiology (cells)...

  4. Structural integrity assessment based on the HFR Petten neutron beam facilities

    CERN Document Server

    Ohms, C; Idsert, P V D

    2002-01-01

    Neutrons are becoming recognized as a valuable tool for structural-integrity assessment of industrial components and advanced materials development. Microstructure, texture and residual stress analyses are commonly performed by neutron diffraction and a joint CEN/ISO Pre-Standard for residual stress analysis is under development. Furthermore neutrons provide for defects analyses, i.e. precipitations, voids, pores and cracks, through small-angle neutron scattering (SANS) or radiography. At the High Flux Reactor, 12 beam tubes have been installed for the extraction of thermal neutrons for such applications. Two of them are equipped with neutron diffractometers for residual stress and structure determination and have been extensively used in the past. Several other facilities are currently being reactivated and upgraded. These include the SANS and radiography facilities as well as a powder diffractometer. This paper summarizes the main characteristics and current status of these facilities as well as recently in...

  5. Neutron measurements at BRIT/BARC medical cyclotron facility of RMC, Parel

    International Nuclear Information System (INIS)

    Sathian, Deepa; Sathian, V.; Phandnis, U.V.; Soni, P.S.; Mohite, D.Y.

    2005-01-01

    Neutron leakage and its long distance propagation in the atmosphere from the intense neutron facilities such as high energy accelerators like Cyclotron are very important for the shielding design of the facilities and resulting dose reduction to nearby population, because of strong penetrability of high energy neutrons. The neutron interaction cross sections are highly energy dependent, so different methods are adopted for measuring different energy neutrons. The method also depends on the amount of neutron fluence rate expected at the location. When the fluence rate is very high, the foil activation is the best method for the measurement of neutron fluence rate. In foil activation technique an inactive material is activated by neutrons and the activity is measured and correlated to the neutron fluence rate. In this paper, neutron fluence rate measurement using different activation foils at medical cyclotron room of Radiation Medicine Centre (RMC) is discussed. (author)

  6. Calculations of neutron spectra after neutron-neutron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, B E [Gettysburg College, Box 405, Gettysburg, PA 17325 (United States); Stephenson, S L [Gettysburg College, Box 405, Gettysburg, PA 17325 (United States); Howell, C R [Duke University and Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States); Mitchell, G E [North Carolina State University, Raleigh, NC 27695-8202 (United States); Tornow, W [Duke University and Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States); Furman, W I [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Lychagin, E V [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Muzichka, A Yu [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Nekhaev, G V [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Strelkov, A V [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Sharapov, E I [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Shvetsov, V N [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation)

    2004-09-01

    A direct neutron-neutron scattering length, a{sub nn}, measurement with the goal of 3% accuracy (0.5 fm) is under preparation at the aperiodic pulsed reactor YAGUAR. A direct measurement of a{sub nn} will not only help resolve conflicting results of a{sub nn} by indirect means, but also in comparison to the proton-proton scattering length, a{sub pp}, shed light on the charge-symmetry of the nuclear force. We discuss in detail the analysis of the nn-scattering data in terms of a simple analytical expression. We also discuss calibration measurements using the time-of-flight spectra of neutrons scattered on He and Ar gases and the neutron activation technique. In particular, we calculate the neutron velocity and time-of-flight spectra after scattering neutrons on neutrons and after scattering neutrons on He and Ar atoms for the proposed experimental geometry, using a realistic neutron flux spectrum-Maxwellian plus epithermal tail. The shape of the neutron spectrum after scattering is appreciably different from the initial spectrum, due to collisions between thermal-thermal and thermal-epithermal neutrons. At the same time, the integral over the Maxwellian part of the realistic scattering spectrum differs by only about 6 per cent from that of a pure Maxwellian nn-scattering spectrum.

  7. Atmospheric Electricity

    Science.gov (United States)

    Aplin, Karen; Fischer, Georg

    2018-02-01

    Electricity occurs in atmospheres across the Solar System planets and beyond, spanning spectacular lightning displays in clouds of water or dust, to more subtle effects of charge and electric fields. On Earth, lightning is likely to have existed for a long time, based on evidence from fossilized lightning strikes in ancient rocks, but observations of planetary lightning are necessarily much more recent. The generation and observations of lightning and other atmospheric electrical processes, both from within-atmosphere measurements, and spacecraft remote sensing, can be readily studied using a comparative planetology approach, with Earth as a model. All atmospheres contain charged molecules, electrons, and/or molecular clusters created by ionization from cosmic rays and other processes, which may affect an atmosphere's energy balance both through aerosol and cloud formation, and direct absorption of radiation. Several planets are anticipated to host a "global electric circuit" by analogy with the circuit occurring on Earth, where thunderstorms drive current of ions or electrons through weakly conductive parts of the atmosphere. This current flow may further modulate an atmosphere's radiative properties through cloud and aerosol effects. Lightning could potentially have implications for life through its effects on atmospheric chemistry and particle transport. It has been observed on many of the Solar System planets (Earth, Jupiter, Saturn, Uranus, and Neptune) and it may also be present on Venus and Mars. On Earth, Jupiter, and Saturn, lightning is thought to be generated in deep water and ice clouds, but discharges can be generated in dust, as for terrestrial volcanic lightning, and on Mars. Other, less well-understood mechanisms causing discharges in non-water clouds also seem likely. The discovery of thousands of exoplanets has recently led to a range of further exotic possibilities for atmospheric electricity, though lightning detection beyond our Solar System

  8. Residual stresses in a cast iron automotive brake disc rotor

    International Nuclear Information System (INIS)

    Ripley, Maurice I.; Kirstein, Oliver

    2006-01-01

    Runout, and consequent juddering and pulsation through the brake pedal, is a multi-million dollar per year warranty problem for car manufacturers. There is some suspicion that the runout can be caused by relaxation of residual casting stresses when the disc is overheated during severe-braking episodes. We report here neutron-diffraction measurements of the levels and distribution of residual strains in a used cast iron brake disc rotor. The difficulties of measuring stresses in grey cast iron are outlined and three-dimensional residual-strain distributions are presented and their possible effects discussed

  9. Progress report on neutron science. April 1, 2006 - March 31, 2007

    International Nuclear Information System (INIS)

    Takeda, Masayasu; Ohhara, Takashi; Moriai, Atsushi

    2008-03-01

    There are 13 research groups in neutron science and technology in the Quantum Beam Science Directorate (QuBS) and Advanced Science Research Center (ASRC) of Japan Atomic Research Agency (JAEA). A wide variety of research is performed by these group: neutron scattering (condensed matter physics, polymer science, biology, and residual stress analysis), prompt gamma-ray analysis, neutron radiography, neutron optics, and development of a neutron spectrometer, neutron beam handling device and neutron detector. This issue summarizes research progress in neutron science and technology including activities of the Nuclear Science and Engineering Directorate of JAEA, and of the COMMON USE PROGRAM of JAEA utilizing the research reactor JRR-3 during the period between April 1, 2006 and March 31, 2007. This report contains highlights of research by these 13 neutron research groups of QuBS and ASRC, introducing 68 experimental reports. (author)

  10. Methods of measuring residual stresses in components

    International Nuclear Information System (INIS)

    Rossini, N.S.; Dassisti, M.; Benyounis, K.Y.; Olabi, A.G.

    2012-01-01

    Highlights: ► Defining the different methods of measuring residual stresses in manufactured components. ► Comprehensive study on the hole drilling, neutron diffraction and other techniques. ► Evaluating advantage and disadvantage of each method. ► Advising the reader with the appropriate method to use. -- Abstract: Residual stresses occur in many manufactured structures and components. Large number of investigations have been carried out to study this phenomenon and its effect on the mechanical characteristics of these components. Over the years, different methods have been developed to measure residual stress for different types of components in order to obtain reliable assessment. The various specific methods have evolved over several decades and their practical applications have greatly benefited from the development of complementary technologies, notably in material cutting, full-field deformation measurement techniques, numerical methods and computing power. These complementary technologies have stimulated advances not only in measurement accuracy and reliability, but also in range of application; much greater detail in residual stresses measurement is now available. This paper aims to classify the different residual stresses measurement methods and to provide an overview of some of the recent advances in this area to help researchers on selecting their techniques among destructive, semi destructive and non-destructive techniques depends on their application and the availabilities of those techniques. For each method scope, physical limitation, advantages and disadvantages are summarized. In the end this paper indicates some promising directions for future developments.

  11. Mars: Atmosphere

    Science.gov (United States)

    Moroz, V.; Murdin, P.

    2001-07-01

    The atmosphere of MARS is much thinner than the terrestrial one. However, even the simplest visual telescopic observations show a set of atmospheric events such as seasonal exchange of material between polar caps, temporal appearance of clouds and changes of visibility of dark regions on the disk of the planet. In 1947 the prominent CO2 bands in the near-infrared part of the Martian spectrum were...

  12. Neutron diffraction from holographic gratings in PMMA

    International Nuclear Information System (INIS)

    Havermeyer, F.; Kraetzig, E.; Rupp, R.A.; Schubert, D.W.

    1999-01-01

    Complete text of publication follows. By definition photorefractive materials change the refractive index for light under the action of light. Using the spatially modulated light intensity pattern from the interference of two plane waves, volume phase gratings with accurately defined spacings can be produced. Depending on the material there are many physical origins for these gratings, but in most cases they are linked to a density modulation and, consequently, to a refractive index grating for neutrons. By diffraction of light or neutrons from such gratings even small refractive index changes down to Δn ∼ 10 -7 - 10 -9 can be measured. In our photopolymer system PMMA/MMA (poly(methyl methacrylate) with a content of 10-20% of the residual monomer methyl methacrylate) inhomogeneous illumination leads to local post-polymerisation processes of the residual monomer. The resulting light-optical refractive index grating is caused by the modulation of the monomer/polymer ratio as well as by the modulation of the total density. Only by the unique combination of methods for light and neutron diffraction, available at HOLONS (Holography and Neutron Scattering, instrument at the GKSS research centre), both contributions can be separated. We discuss the angular dependence of the neutron diffraction efficiency for weakly and strongly (efficiencies up to 60% have been achieved) modulated gratings and propose a simple model for the evaluation of the gratings. (author)

  13. Neutron flux measuring system for nuclear reactor

    International Nuclear Information System (INIS)

    Aoki, Kazuo.

    1977-01-01

    Purpose: To avoid the generation of an undesired scram signal due to abrupt changes in the neutron level given to the detectors disposed near the boundary between the moderator and the atmosphere. Constitution: In a nuclear reactor adapted to conduct power control by the change of the level in the moderator such as heavy water, the outputs from the neutron detectors disposed vertically are averaged and the nuclear reactor is scramed corresponding to the averaged value. In this system, moderator level detectors are additionally provided to the nuclear reactor and their outputs, moderator level signal, are sent to a power averaging device where the output signals of the neutron detectors are judged if they are delivered from neutrons in the moderator or not depending on the magnitude of the level signal and the outputs of the detectors out of the moderator are substantially excluded. The reactor interlock signal from the device is utilized as a scram signal. (Seki, T.)

  14. Fluidised-bed combustion of gasification residue

    Energy Technology Data Exchange (ETDEWEB)

    Korpela, T.; Kudjoi, A.; Hippinen, I.; Heinolainen, A.; Suominen, M.; Lu Yong [Helsinki Univ. of Technology (Finland). Lab of Energy Economics and Power Plant Engineering

    1996-12-01

    Partial gasification processes have been presented as possibilities for future power production. In the processes, the solid materials removed from a gasifier (i.e. fly ash and bed material) contain unburnt fuel and the fuel conversion is increased by burning this gasification residue either in an atmospheric or a pressurised fluidised-bed. In this project, which is a part of European JOULE 2 EXTENSION research programme, the main research objectives are the behaviour of calcium and sulphur compounds in solids and the emissions of sulphur dioxide and nitrogen oxides (NO{sub x} and N{sub 2}O) in pressurised fluidised-bed combustion of gasification residues. (author)

  15. Neutron matter, symmetry energy and neutron stars

    Energy Technology Data Exchange (ETDEWEB)

    Stefano, Gandolfi [Los Alamos National Laboratory (LANL); Steiner, Andrew W [ORNL

    2016-01-01

    Recent progress in quantum Monte Carlo with modern nucleon-nucleon interactions have enabled the successful description of properties of light nuclei and neutron-rich matter. Of particular interest is the nuclear symmetry energy, the energy cost of creating an isospin asymmetry, and its connection to the structure of neutron stars. Combining these advances with recent observations of neutron star masses and radii gives insight into the equation of state of neutron-rich matter near and above the saturation density. In particular, neutron star radius measurements constrain the derivative of the symmetry energy.

  16. Directional epithermal neutron detector

    International Nuclear Information System (INIS)

    Givens, W.W.; Mills, W.R. Jr.

    1986-01-01

    A borehole tool for epithermal neutron die-away logging of subterranean formations surrounding a borehole is described which consists of: (a) a pulsed source of fast neutrons for irradiating the formations surrounding a borehole, (b) at least one neutron counter for counting epithermal neutrons returning to the borehole from the irradiated formations, (c) a neutron moderating material, (d) an outer thermal neutron shield providing a housing for the counter and the moderating material, (e) an inner thermal neutron shield dividing the housing so as to provide a first compartment bounded by the inner thermal neutron shield and a first portion of the outer thermal neutron shield and a second compartment bounded by the inner thermal neutron shield and a second portion of the outer thermal neutron shield, the counter being positioned within the first compartment and the moderating material being positioned within the second compartment, and (f) means for positioning the borehole tool against one side of the borehole wall and azimuthally orienting the borehole tool such that the first chamber is in juxtaposition with the borehole wall, the formation epithermal neutrons penetrating into the first chamber through the first portion of the outer thermal neutron shield are detected by the neutron counter for die-away measurement, thereby maximizing the directional sensitivty of the neutron counter to formation epithermal neutrons, the borehole fluid epithermal neutrons penetrating into the second chamber through the second chamber through the second portion of the outer thermal neutron shield are largely slowed down and lowered in energy by the moderating material and absorbed by the inner thermal neutron shield before penetrating into the first chamber, thereby minimizing the directional sensitivity of the neutron counter to borehole fluid epithermal neutrons

  17. Residual gas analysis

    International Nuclear Information System (INIS)

    Berecz, I.

    1982-01-01

    Determination of the residual gas composition in vacuum systems by a special mass spectrometric method was presented. The quadrupole mass spectrometer (QMS) and its application in thin film technology was discussed. Results, partial pressure versus time curves as well as the line spectra of the residual gases in case of the vaporization of a Ti-Pd-Au alloy were demonstrated together with the possible construction schemes of QMS residual gas analysers. (Sz.J.)

  18. Powder neutron diffractometers

    International Nuclear Information System (INIS)

    Adib, M.

    2002-01-01

    Basic properties and applications of powder neutron Diffractometers are described for optimum use of the continuous neutron beams. These instruments are equipped with position sensitive detectors, neutron guide tubes, and both high intensity and high resolution modes of operation are possible .The principles of both direct and Fourier reverse time-of-flight neutron Diffractometers are also given

  19. Neutron dosimetry - A review

    Energy Technology Data Exchange (ETDEWEB)

    Baum, J W

    1955-03-29

    This review summarizes information on the following subjects: (1) physical processes of importance in neutron dosimetry; (2) biological effects of neutrons; (3) neutron sources; and (4) instruments and methods used in neutron dosimetry. Also, possible improvements in dosimetry instrumentation are outlined and discussed. (author)

  20. Neutron scattering. Lectures

    Energy Technology Data Exchange (ETDEWEB)

    Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner [eds.

    2010-07-01

    The following topics are dealt with: Neutron sources, symmetry of crystals, diffraction, nanostructures investigated by small-angle neutron scattering, the structure of macromolecules, spin dependent and magnetic scattering, structural analysis, neutron reflectometry, magnetic nanostructures, inelastic scattering, strongly correlated electrons, dynamics of macromolecules, applications of neutron scattering. (HSI)

  1. Neutron generator control system

    International Nuclear Information System (INIS)

    Peelman, H.E.; Bridges, J.R.

    1981-01-01

    A method is described of controlling the neutron output of a neutron generator tube used in neutron well logging. The system operates by monitoring the target beam current and comparing a function of this current with a reference voltage level to develop a control signal used in a series regulator to control the replenisher current of the neutron generator tube. (U.K.)

  2. Genetic effect of neutrons

    International Nuclear Information System (INIS)

    Luchnik, N.V.; Sevan'kaev, A.V.; Fesenko, Eh.V.

    1984-01-01

    Gene mutations resulting from neutron effect are considered, but attention is focused on chromosome mutations. Dose curves for different energy of neutrons obtained at different objects are obtained which makes it possible to consider RBE of neutrons depending on their energy and radiation dose and to get some information on the neutron effect on heredity

  3. Neutron scattering. Lectures

    International Nuclear Information System (INIS)

    Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner

    2010-01-01

    The following topics are dealt with: Neutron sources, symmetry of crystals, diffraction, nanostructures investigated by small-angle neutron scattering, the structure of macromolecules, spin dependent and magnetic scattering, structural analysis, neutron reflectometry, magnetic nanostructures, inelastic scattering, strongly correlated electrons, dynamics of macromolecules, applications of neutron scattering. (HSI)

  4. Study of residual stresses in CT test specimens welded by electron beam

    Science.gov (United States)

    Papushkin, I. V.; Kaisheva, D.; Bokuchava, G. D.; Angelov, V.; Petrov, P.

    2018-03-01

    The paper reports result of residual stress distribution studies in CT specimens reconstituted by electron beam welding (EBW). The main aim of the study is evaluation of the applicability of the welding technique for CT specimens’ reconstitution. Thus, the temperature distribution during electron beam welding of a CT specimen was calculated using Green’s functions and the residual stress distribution was determined experimentally using neutron diffraction. Time-of-flight neutron diffraction experiments were performed on a Fourier stress diffractometer at the IBR-2 fast pulsed reactor in FLNP JINR (Dubna, Russia). The neutron diffraction data estimates yielded a maximal stress level of ±180 MPa in the welded joint.

  5. Neutron polarization in polarized 3He targets

    International Nuclear Information System (INIS)

    Friar, J.L.; Gibson, B.F.; Payne, G.L.; Bernstein, A.M.; Chupp, T.E.

    1990-01-01

    Simple formulas for the neutron and proton polarizations in polarized 3 He targets are derived assuming (1) quasielastic final states; (2) no final-state interactions; (3) no meson-exchange currents; (4) large momentum transfers; (5) factorizability of 3 He SU(4) response-function components. Numerical results from a wide variety of bound-state solutions of the Faddeev equations are presented. It is found that this simple model predicts the polarization of neutrons in a fully polarized 3 He target to be 87%, while protons should have a slight residual polarization of -2.7%. Numerical studies show that this model works very well for quasielastic electron scattering

  6. Neutronics of pulsed spallation neutron sources

    International Nuclear Information System (INIS)

    Watanabe, Noboru

    2003-01-01

    Various topics and issues on the neutronics of pulsed spallation neutron sources, mainly for neutron scattering experiments, are reviewed to give a wide circle of readers a better understanding of these sources in order to achieve a high neutronic performance. Starting from what neutrons are needed, what the spallation reaction is and how to produce slow-neutrons more efficiently, the outline of the target and moderator neutronics are explained. Various efforts with some new concepts or ideas have already been devoted to obtaining the highest possible slow-neutron intensity with desired pulse characteristics. This paper also reviews the recent progress of such efforts, mainly focused on moderator neutronics, since moderators are the final devices of a neutron source, which determine the source performance. Various governing parameters for neutron-pulse characteristics such as material issues, geometrical parameters (shape and dimensions), the target-moderator coupling scheme, the ortho-para-hydrogen ratio, poisoning, etc are discussed, aiming at a high performance pulsed spallation source

  7. Neutron shieldings

    International Nuclear Information System (INIS)

    Tarutani, Kohei

    1979-01-01

    Purpose: To decrease the stresses resulted by the core bendings to the base of an entrance nozzle. Constitution: Three types of round shielding rods of different diameter are arranged in a hexagonal tube. The hexagonal tube is provided with several spacer pads receiving the loads from the core constrain mechanism at its outer circumference, a handling head for a fuel exchanger at its top and an entrance nozzle for self-holding the neutron shieldings and flowing heat-removing coolants at its bottom. The diameters for R 1 , R 2 and R 3 for the round shielding rods are designed as: 0.1 R 1 2 1 and 0.2 R 1 2 1 . Since a plurality of shielding rods of small diameter are provided, soft structure are obtained and a plurality of coolant paths are formed. (Furukawa, Y.)

  8. Residual stress in a thick section high strength T-butt weld

    International Nuclear Information System (INIS)

    Pearce, S.V.; Linton, V.M.; Oliver, E.C.

    2008-01-01

    Residual stresses in a structure are generated as a result of the various fabrication and welding processes used to make the component. Being able to quantify these residual stresses is a key step in determining the continuing integrity of a structure in service. In this work, the residual stresses around a high strength, quenched and tempered steel T-butt web to curved plate weld have been measured using neutron strain scanning. The results show that the residual stresses near the weld were dominated by the welding residual stresses, while the stresses further from the weld were dominated by the bending residual stresses. The results suggest that the combination of welding-induced residual stress and significant pre-welding residual stress, as in the case of a thick bent section of plate can significantly alter the residual stress profile from that in a flat plate

  9. Miscellaneous neutron techniques

    International Nuclear Information System (INIS)

    Iddings, F.A.

    1976-01-01

    Attention is brought to the less often uses of neutrons in the areas of neutron radiography, well logging, and neutron gaging. Emphasis on neutron radiography points toward the isotopic sensitivity of the method versus the classical bulk applications. Also recognized is the ability of neutron radiography to produce image changes that correspond to thickness and density changes obtained in photon radiography. Similarly, neutron gaging applications center on the measurement of radiography. Similarly, neutron gaging applications center on the measurement of water, oil, or plastics in industrial samples. Well logging extends the neutron gaging to encompass many neutron properties and reactions besides thermalization and capture. Neutron gaging also gives information on organic structure and concentrations of a variety of elements or specific compounds in selected matrices

  10. Nuclear reactor neutron shielding

    Science.gov (United States)

    Speaker, Daniel P; Neeley, Gary W; Inman, James B

    2017-09-12

    A nuclear reactor includes a reactor pressure vessel and a nuclear reactor core comprising fissile material disposed in a lower portion of the reactor pressure vessel. The lower portion of the reactor pressure vessel is disposed in a reactor cavity. An annular neutron stop is located at an elevation above the uppermost elevation of the nuclear reactor core. The annular neutron stop comprises neutron absorbing material filling an annular gap between the reactor pressure vessel and the wall of the reactor cavity. The annular neutron stop may comprise an outer neutron stop ring attached to the wall of the reactor cavity, and an inner neutron stop ring attached to the reactor pressure vessel. An excore instrument guide tube penetrates through the annular neutron stop, and a neutron plug comprising neutron absorbing material is disposed in the tube at the penetration through the neutron stop.

  11. Relaxation of residual stress in MMC after combined plastic deformation and heat treatment

    International Nuclear Information System (INIS)

    Bruno, G.; Ceretti, M.; Girardin, E.; Giuliani, A.; Manescu, A.

    2004-01-01

    Neutron Diffraction shows that plastic pre-deformation and heat treatments have opposite effects on the residual stress in Al-SiC p composites. The thermal micro residual stress is relaxed or even reversed by pre-strains above 0.2%, but restored by heat treatments. The sense of relaxation changes above 400 deg. C (the mixing temperature)

  12. Diffraction measurements of residual stress in titanium matrix composites

    International Nuclear Information System (INIS)

    James, M.R.; Bourke, M.A.; Goldstone, J.A.; Lawson, A.C.

    1993-01-01

    Metal matrix composites develop residual strains after consolidation due to the thermal expansion mismatch between the reinforcement fiber and the matrix. X-ray and neutron diffraction measured values for the longitudinal residual stress in the matrix of four titanium MMCs are reported. For thick composites (> 6 plies) the surface stress measured by x-ray diffraction matches that determined by neutron diffraction and therefore represents the stress in the bulk region consisting of the fibers and matrix. For thin sheet composites, the surface values are lower than in the interior and increase as the outer rows of fibers are approached. While a rationale for the behavior in the thin sheet has yet to be developed, accounting for composite thickness is important when using x-ray measured values to validate analytic and finite element calculations of the residual stress state

  13. Atmospheric Photochemistry

    Science.gov (United States)

    Massey, Harrie; Potter, A. E.

    1961-01-01

    The upper atmosphere offers a vast photochemical laboratory free from solid surfaces, so all reactions take place in the gaseous phase. At 30 km altitude the pressure has fallen to about one-hundredth of that at ground level, and we shall, rather arbitrarily, regard the upper atmosphere as beginning at that height. By a little less than 100 km the pressure has fallen to 10(exp -3) mm Hg and is decreasing by a power of ten for every 15 km increase in altitude. Essentially we are concerned then with the photochemistry of a nitrogen-oxygen mixture under low-pressure conditions in which photo-ionization, as well as photodissociation, plays an important part. Account must also be taken of the presence of rare constituents, such as water vapour and its decomposition products, including particularly hydroxyl, oxides of carbon, methane and, strangely enough, sodium, lithium and calcium. Many curious and unfamiliar reactions occur in the upper atmosphere. Some of them are luminescent, causing the atmosphere to emit a dim light called the airglow. Others, between gaseous ions and neutral molecules, are almost a complete mystery at this time. Similar interesting phenomena must occur in other planetary atmospheres, and they might be predicted if sufficient chemical information were available.

  14. Secondary standard neutron detector for measuring total reaction cross sections

    International Nuclear Information System (INIS)

    Sekharan, K.K.; Laumer, H.; Gabbard, F.

    1975-01-01

    A neutron detector has been constructed and calibrated for the accurate measurement of total neutron-production cross sections. The detector consists of a polyethylene sphere of 24'' diameter in which 8- 10 BF 3 counters have been installed radially. The relative efficiency of this detector has been determined for average neutron energies, from 30 keV to 1.5 MeV by counting neutrons from 7 Li(p,n) 7 Be. By adjusting the radial positions of the BF 3 counters in the polyethylene sphere the efficiency for neutron detection was made nearly constant for this energy range. Measurement of absolute efficiency for the same neutron energy range has been done by counting the neutrons from 51 V(p,n) 51 Cr and 57 Fe(p,n) 57 Co reactions and determining the absolute number of residual nuclei produced during the measurement of neutron yield. Details of absolute efficiency measurements and the use of the detector for measurement of total neutron yields from neutron producing reactions such as 23 Na(p,n) 23 Mg are given

  15. Atmospheric Ionizing Radiation and Human Exposure

    Science.gov (United States)

    Wilson, John W.; Mertens, Christopher J.; Goldhagen, Paul; Friedberg, W.; DeAngelis, G.; Clem, J. M.; Copeland, K.; Bidasaria, H. B.

    2005-01-01

    Atmospheric ionizing radiation is of interest, apart from its main concern of aircraft exposures, because it is a principal source of human exposure to radiations with high linear energy transfer (LET). The ionizing radiations of the lower atmosphere near the Earth s surface tend to be dominated by the terrestrial radioisotopes. especially along the coastal plain and interior low lands, and have only minor contributions from neutrons (11 percent). The world average is substantially larger but the high altitude cities especially have substantial contributions from neutrons (25 to 45 percent). Understanding the world distribution of neutron exposures requires an improved understanding of the latitudinal, longitudinal, altitude and spectral distribution that depends on local terrain and time. These issues are being investigated in a combined experimental and theoretical program. This paper will give an overview of human exposures and describe the development of improved environmental models.

  16. Atmospheric Ionizing Radiation and Human Exposure

    Science.gov (United States)

    Wilson, J. W.; Goldhagen, P.; Friedberg, W.; DeAngelis, G.; Clem, J. M.; Copeland, K.; Bidasaria, H. B.

    2004-01-01

    Atmospheric ionizing radiation is of interest, apart from its main concern of aircraft exposures, because it is a principal source of human exposure to radiations with high linear energy transfer (LET). The ionizing radiations of the lower atmosphere near the Earth s surface tend to be dominated by the terrestrial radioisotopes especially along the coastal plain and interior low lands and have only minor contributions from neutrons (11 percent). The world average is substantially larger but the high altitude cities especially have substantial contributions from neutrons (25 to 45 percent). Understanding the world distribution of neutron exposures requires an improved understanding of the latitudinal, longitudinal, altitude and spectral distribution that depends on local terrain and time. These issues are being investigated in a combined experimental and theoretical program. This paper will give an overview of human exposures and describe the development of improved environmental models.

  17. Atmospheric thermodynamics

    CERN Document Server

    Iribarne, J V

    1973-01-01

    The thermodynamics of the atmosphere is the subject of several chapters in most textbooks on dynamic meteorology, but there is no work in English to give the subject a specific and more extensive treatment. In writing the present textbook, we have tried to fill this rather remarkable gap in the literature related to atmospheric sciences. Our aim has been to provide students of meteorology with a book that can playa role similar to the textbooks on chemical thermodynamics for the chemists. This implies a previous knowledge of general thermodynamics, such as students acquire in general physics courses; therefore, although the basic principles are reviewed (in the first four chapters), they are only briefly discussed, and emphasis is laid on those topics that will be useful in later chapters, through their application to atmospheric problems. No attempt has been made to introduce the thermodynamics of irreversible processes; on the other hand, consideration of heterogeneous and open homogeneous systems permits a...

  18. Atmospheric pollution

    International Nuclear Information System (INIS)

    Lambrozo, J.; Guillossou, G.

    2008-01-01

    The atmosphere is the reservoir of numerous pollutants (nitrogen oxides, sulfur oxides, carbon oxides, particulates, volatile organic compounds, polycyclic aromatic hydrocarbons) from natural origin or anthropogenic origin ( industry, transport, agriculture, district heating). With epidemiologic studies the atmospheric pollution is associated with an increase of respiratory and cardiovascular diseases. At the european level, the technological progress, the legislation have allowed a reduction of pollutant emissions, however these efforts have to be continued because the sanitary impact of atmospheric pollution must not be underestimated, even if the risks appear less important that these ones in relation with tobacco, inside pollution or others factors of cardiovascular risks. Indeed, on these last factors an individual action is possible for the exposure to air pollution people have no control. (N.C.)

  19. The representation of neutron polarization

    International Nuclear Information System (INIS)

    Byrne, J.

    1979-01-01

    Neutron beam polarization representation is discussed under the headings; transfer matrices, coherent parity violation for neutrons, neutron spin rotation in helical magnetic fields, polarization and interference. (UK)

  20. Pulsed neutron sources for epithermal neutrons

    International Nuclear Information System (INIS)

    Windsor, C.G.

    1978-01-01

    It is shown how accelerator based neutron sources, giving a fast neutron pulse of short duration compared to the neutron moderation time, promise to open up a new field of epithermal neutron scattering. The three principal methods of fast neutron production: electrons, protons and fission boosters will be compared. Pulsed reactors are less suitable for epithermal neutrons and will only be briefly mentioned. The design principle of the target producing fast neutrons, the moderator and reflector to slow them down to epithermal energies, and the cell with its beam tubes and shielding will all be described with examples taken from the new Harwell electron linac to be commissioned in 1978. A general comparison of pulsed neutron performance with reactors is fraught with difficulties but has been attempted. Calculation of the new pulsed source fluxes and pulse widths is now being performed but we have taken the practical course of basing all comparisons on extrapolations from measurements on the old 1958 Harwell electron linac. Comparisons for time-of-flight and crystal monochromator experiments show reactors to be at their best at long wavelengths, at coarse resolution, and for experiments needing a specific incident wavelength. Even existing pulsed sources are shown to compete with the high flux reactors in experiments where the hot neutron flux and the time-of-flight methods can be best exploited. The sources under construction can open a new field of inelastic neutron scattering based on energy transfer up to an electron volt and beyond

  1. On-line measurement of residual monomer during polymerisation of acrylamide using ultrasonics

    International Nuclear Information System (INIS)

    Ponraju, D.; Sebastian, Letha; Viswanathan, S.; Natarajan, A.; Palanichamy, P.; Jayakumar, T.; Baldev Raj

    1996-01-01

    An ultrasonic technique for the estimation of residual acrylamide monomer during the polymerization of aqueous acrylamide solution has been investigated. Polyacrylamide gel medium serves as a sensitive medium for detection and dosimetry of fast and thermal neutrons. This technique is based on the fact that the velocity of ultrasonic wave increases with the increase in elasticity due to polymerization. The percentage of residual acrylamide monomer is estimated using ultraviolet spectrophotometric analysis. The ultrasonic velocity is correlated with the residual monomer concentration

  2. Alarming atmospheres

    DEFF Research Database (Denmark)

    Højlund, Marie; Kinch, Sofie

    2014-01-01

    Nurses working in the Neuro-Intensive Care Unit at Aarhus University Hospital lack the tools to prepare children for the alarming atmosphere they will enter when visiting a hospitalised relative. The complex soundscape dominated by alarms and sounds from equipment is mentioned as the main stressor...

  3. Transmutation of Minor Actinide in well thermalized neutron field and application of advanced neutron source (ANS)

    International Nuclear Information System (INIS)

    Iwasaki, Tomohiko; Hirakawa, Naohiro

    1995-01-01

    Transmutation of Minor Actinide (MA) in a well thermalized neutron field was studied. Since MA nuclides have large effective cross sections in the well thermalized neutron field, the transmutation in the well thermalized neutron field has an advantage of high transmutation rate. However, the transmutation rate largely decreases by accumulation of 246 Cm when MA is transmuted only in the well thermalized neutron field for a long period. An acceleration method of burn-up of 246 Cm was studied. High transmutation rate can be obtained by providing a neutron field with high flux in the energy region between 1 and 100 eV. Two stage transmutation using the well thermalized neutron field and this field can transmute MA rapidly. The applicability of the Advanced Neutron Source (ANS) to the transmutation of MA was examined for a typical MA with the composition in the high-level waste generated in the conventional PWR. If the ANS is applied without changing the fuel inventory, the amount of MA which corresponds to that produced by a conventional 1,175 MWe PWR in one year can be transmuted by the ANS in one year. Furthermore, the amount of the residual can be reduced to about 1g (10 -5 of the initial MA weight) by continuing the transmutation for 5 years owing to the two stage transmutation. (author)

  4. Neutron in biology

    Energy Technology Data Exchange (ETDEWEB)

    Niimura, Nobuo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-11-01

    Neutron in biology can provide an experimental method of directly locating relationship of proteins and DNA. However, there are relatively few experimental study of such objects since it takes a lot of time to collect a sufficient number of Bragg reflections and inelastic spectra due to the low flux of neutron illuminating the sample. Since a next generation neutron source of JAERI will be 5MW spallation neutron source and its effective neutron flux will be 10{sup 2} to 10{sup 3} times higher than the one of JRR-3M, neutron in biology will open a completely new world for structural biology. (author)

  5. Layered semiconductor neutron detectors

    Science.gov (United States)

    Mao, Samuel S; Perry, Dale L

    2013-12-10

    Room temperature operating solid state hand held neutron detectors integrate one or more relatively thin layers of a high neutron interaction cross-section element or materials with semiconductor detectors. The high neutron interaction cross-section element (e.g., Gd, B or Li) or materials comprising at least one high neutron interaction cross-section element can be in the form of unstructured layers or micro- or nano-structured arrays. Such architecture provides high efficiency neutron detector devices by capturing substantially more carriers produced from high energy .alpha.-particles or .gamma.-photons generated by neutron interaction.

  6. Neutron in biology

    International Nuclear Information System (INIS)

    Niimura, Nobuo

    1997-01-01

    Neutron in biology can provide an experimental method of directly locating relationship of proteins and DNA. However, there are relatively few experimental study of such objects since it takes a lot of time to collect a sufficient number of Bragg reflections and inelastic spectra due to the low flux of neutron illuminating the sample. Since a next generation neutron source of JAERI will be 5MW spallation neutron source and its effective neutron flux will be 10 2 to 10 3 times higher than the one of JRR-3M, neutron in biology will open a completely new world for structural biology. (author)

  7. A neutron activation detector

    International Nuclear Information System (INIS)

    Ambardanishvili, T.S.; Kolomiitsev, M.A.; Zakharina, T.Y.; Dundua, V.J.; Chikhladze, N.V.

    1973-01-01

    The present invention concerns a neutron activation detector made from a moulded and hardened composition. According to the invention, that composition contains an activable substance constituted by at least two chemical elements and/or compounds of at least two chemical elements. Each of these chemical elements is capable of reacting with the neutrons forming radio-active isotopes with vatious levels of energy during desintegration. This neutron detector is mainly suitable for measuring integral thermal neutron and fast neutron fluxes during irradiation of the sample, and also for measuring the intensities of neutron fields [fr

  8. Very slow neutrons

    International Nuclear Information System (INIS)

    Frank, A.

    1983-01-01

    The history is briefly presented of the research so far of very slow neutrons and their basic properties are explained. The methods are described of obtaining very slow neutrons and the problems of their preservation are discussed. The existence of very slow neutrons makes it possible to perform experiments which may deepen the knowledge of the fundamental properties of neutrons. Their wavelength approximates that of visible radiation. The possibilities and use are discussed of neutron optical systems (neutron microscope) which could be an effective instrument for the study of the detailed arrangement, especially of organic substances. (B.S.)

  9. Reactor neutron dosimetry

    International Nuclear Information System (INIS)

    Najzer, M.; Pauko, M.; Glumac, B.; Acquah, I.N.; Moskon, F.

    1977-01-01

    An analysis of requirements and possibilities for experimental neutron spectrum determination during the reactor pressure vessel surveil lance programme is given. Fast neutron spectrum and neutron dose rate were measured in the Fast neutron irradiation facility of our TRIGA reactor. It was shown that the facility can be used for calibration of neutron dosimeters and for irradiation of samples sensitive to neutron radiation. The investigation of the unfolding algorithm ITER was continued. Based on this investigations are two specialized unfolding program packages ITERAD and ITERGS written this year. They are able to unfold data from activation detectors and NaI(T1) gamma spectrometer respectively

  10. Long distance propagation of a polarized neutron beam in zero magnetic field

    International Nuclear Information System (INIS)

    Schmidt, U.; Bitter, T.; El-Muzeini, P.

    1992-01-01

    A beam of fully polarized cold neutrons was transported through a zero magnetic field region of 70 m length without loss of polarization. The purpose of this exercise was twofold: Firstly, to demonstrate that the new zero-field neutron spin-echo method will work also for very long neutron flight paths; secondly, to prove in the most direct way that the neutron free-flight region of the ILL neutron-antineutron oscillation experiment was indeed sufficiently field-free ('quasifree condition') by using the neutrons themselves as a magnetometer. To this purpose the residual magnetic field integrals in the long 'zero-field' region were measured with a conventional neutron spin-echo method. The overall spin precession angle of the neutrons during their flight through the long zero-field region was found to be less than 2 0 . (orig.)

  11. Salient features, response and operation of Lead-Free Gulmarg Neutron Monitor

    International Nuclear Information System (INIS)

    Mufti, S.; Chatterjee, S.; Ishtiaq, P.M.; Darzi, M.A.; Mir, T.A.; Shah, G.N.

    2016-01-01

    Lead-Free Gulmarg Neutron Monitor (LFGNM) provides continuous ground level intensity measurements of atmospheric secondary neutrons produced in interactions of primary cosmic rays with the Earth's constituent atmosphere. We report the LFGNM detector salient features and simulation of its energy response for 10"−"1"1 MeV to 10"4 MeV energy incident neutrons using the FLUKA Monte Carlo package. An empirical calibration of the LFGNM detector carried out with a Pu–Be neutron source for maximising its few MeV neutron counting sensitivity is also presented. As an illustration of its functionality a single representative transient solar modulation event recorded by LFGNM depicting Forbush decrease in integrated neutron data for which the geospace consequences are well known is also presented. Performance of LFGNM under actual observation conditions for effectively responding to transient solar modulation is seen to compare well with other world-wide conventional neutron monitors.

  12. A novel approach to correct the coded aperture misalignment for fast neutron imaging

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, F. N.; Hu, H. S., E-mail: huasi-hu@mail.xjtu.edu.cn; Wang, D. M.; Jia, J. [School of Energy and Power Engineering, Xi’an Jiaotong University, Xi’an 710049 (China); Zhang, T. K. [Laser Fusion Research Center, CAEP, Mianyang, 621900 Sichuan (China); Jia, Q. G. [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China)

    2015-12-15

    Aperture alignment is crucial for the diagnosis of neutron imaging because it has significant impact on the coding imaging and the understanding of the neutron source. In our previous studies on the neutron imaging system with coded aperture for large field of view, “residual watermark,” certain extra information that overlies reconstructed image and has nothing to do with the source is discovered if the peak normalization is employed in genetic algorithms (GA) to reconstruct the source image. Some studies on basic properties of residual watermark indicate that the residual watermark can characterize coded aperture and can thus be used to determine the location of coded aperture relative to the system axis. In this paper, we have further analyzed the essential conditions for the existence of residual watermark and the requirements of the reconstruction algorithm for the emergence of residual watermark. A gamma coded imaging experiment has been performed to verify the existence of residual watermark. Based on the residual watermark, a correction method for the aperture misalignment has been studied. A multiple linear regression model of the position of coded aperture axis, the position of residual watermark center, and the gray barycenter of neutron source with twenty training samples has been set up. Using the regression model and verification samples, we have found the position of the coded aperture axis relative to the system axis with an accuracy of approximately 20 μm. Conclusively, a novel approach has been established to correct the coded aperture misalignment for fast neutron coded imaging.

  13. Neutron stochastic transport theory with delayed neutrons

    International Nuclear Information System (INIS)

    Munoz-Cobo, J.L.; Verdu, G.

    1987-01-01

    From the stochastic transport theory with delayed neutrons, the Boltzmann transport equation with delayed neutrons for the average flux emerges in a natural way without recourse to any approximation. From this theory a general expression is obtained for the Feynman Y-function when delayed neutrons are included. The single mode approximation for the particular case of a subcritical assembly is developed, and it is shown that Y-function reduces to the familiar expression quoted in many books, when delayed neutrons are not considered, and spatial and source effects are not included. (author)

  14. Neutron Larmor diffraction measurements for materials science

    International Nuclear Information System (INIS)

    Repper, J.; Keller, T.; Hofmann, M.; Krempaszky, C.; Petry, W.; Werner, E.

    2010-01-01

    Neutron Larmor diffraction (LD) is a high-resolution diffraction technique based on the Larmor precession of polarized neutrons. In contrast to conventional diffraction, LD does not depend on the accurate measurement of Bragg angles, and thus the resolution is independent of the beam collimation and monochromaticity. At present, a relative resolution for the determination of the crystal lattice spacing d of Δd/d∼10 -6 is achieved, i.e. at least one order of magnitude superior to conventional neutron or X-ray techniques. This work is a first step to explore the application of LD to high-resolution problems in the analysis of residual stresses, where both the accurate measurement of absolute d values and the possibility of measuring type II and III stresses may provide additional information beyond those accessible by conventional diffraction techniques. Data obtained from Inconel 718 samples are presented.

  15. Neutron Larmor diffraction measurements for materials science

    Energy Technology Data Exchange (ETDEWEB)

    Repper, J., E-mail: julia_repper@web.de [Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM II), TU Muenchen, 85747 Garching (Germany); Keller, T. [Max-Planck-Institut fuer Festkoerperforschung, 70569 Stuttgart (Germany)] [Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM II), TU Muenchen, 85747 Garching (Germany); Hofmann, M. [Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM II), TU Muenchen, 85747 Garching (Germany); Krempaszky, C. [Christian-Doppler-Labor fuer Werkstoffmechanik von Hochleistungslegierungen, TU Muenchen, 85747 Garching (Germany); Petry, W. [Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM II), TU Muenchen, 85747 Garching (Germany); Werner, E. [Lehrstuhl fuer Werkstoffkunde und Werkstoffmechanik, TU Muenchen, 85747 Garching (Germany)

    2010-05-15

    Neutron Larmor diffraction (LD) is a high-resolution diffraction technique based on the Larmor precession of polarized neutrons. In contrast to conventional diffraction, LD does not depend on the accurate measurement of Bragg angles, and thus the resolution is independent of the beam collimation and monochromaticity. At present, a relative resolution for the determination of the crystal lattice spacing d of {Delta}d/d{approx}10{sup -6} is achieved, i.e. at least one order of magnitude superior to conventional neutron or X-ray techniques. This work is a first step to explore the application of LD to high-resolution problems in the analysis of residual stresses, where both the accurate measurement of absolute d values and the possibility of measuring type II and III stresses may provide additional information beyond those accessible by conventional diffraction techniques. Data obtained from Inconel 718 samples are presented.

  16. Inelastic neutron scattering from cerium under pressure

    International Nuclear Information System (INIS)

    Rainford, B.D.; Buras, B.; Lebech, B.

    1976-01-01

    Inelastic neutron scattering from Ce metal at 300K was studied both below and above the first order γ-α phase transition, using a triple axis spectrometer. It was found that (a) there is no indication of any residual magnetic scattering in the collapsed α phase and (b) the energy width of the paramagnetic scattering in the γ-phase increases with pressure. (Auth.)

  17. Microdefects in neutron-transmutationaly doped silicon

    International Nuclear Information System (INIS)

    Vysotskaya, V.V.; Gorin, S.N.; Gres'kov, I.M.; Sobolev, N.A.; Shek, E.I.

    1988-01-01

    Using the method of X-ray topography and high-voltage electron microscopy, the nature of microdefects and character of their changes in neutron-transmutationaly doped silicon depending on the sample prehistory and heat treatment (HT) conditions are refined. It is shown that the microstructure of neutron-transmutationaly doped dislocation-free silicon crystals depends on conditions of ingot growth and post-radiation annealing environment. Annealing in chlorine-containing atmosphere removes microdefects (MD), although in vacuum, argon or air growing MD are preserved and new MD are formed

  18. Microdefects in neutron-transmutationaly doped silicon

    Energy Technology Data Exchange (ETDEWEB)

    Vysotskaya, V V; Gorin, S N; Gres' kov, I M; Sobolev, N A; Shek, E I

    1988-03-01

    Using the method of X-ray topography and high-voltage electron microscopy, the nature of microdefects and character of their changes in neutron-transmutationaly doped silicon depending on the sample prehistory and heat treatment (HT) conditions are refined. It is shown that the microstructure of neutron-transmutationaly doped dislocation-free silicon crystals depends on conditions of ingot growth and post-radiation annealing environment. Annealing in chlorine-containing atmosphere removes microdefects (MD), although in vacuum, argon or air growing MD are preserved and new MD are formed.

  19. Neutron Beam Filters

    International Nuclear Information System (INIS)

    Adib, M.

    2011-01-01

    The purpose of filters is to transmit neutrons with selected energy, while remove unwanted ones from the incident neutron beam. This reduces the background, and the number of spurious. The types of commonly used now-a-day neutron filters and their properties are discussed in the present work. There are three major types of neutron filters. The first type is filter of selective thermal neutron. It transmits the main reflected neutrons from a crystal monochromate, while reject the higher order contaminations accompanying the main one. Beams coming from the moderator always contain unwanted radiation like fast neutrons and gamma-rays which contribute to experimental background and to the biological hazard potential. Such filter type is called filter of whole thermal neutron spectrum. The third filter type is it transmits neutrons with energies in the resonance energy range (En . 1 KeV). The main idea of such neutron filter technique is the use of large quantities of a certain material which have the deep interference minima in its total neutron cross-section. By transmitting reactor neutrons through bulk layer of such material, one can obtain the quasimonochromatic neutron lines instead of white reactor spectrum.

  20. Neutron anatomy

    Energy Technology Data Exchange (ETDEWEB)

    Bacon, G.E. [Univ. of Sheffield (United Kingdom)

    1994-12-31

    The familiar extremes of crystalline material are single-crystals and random powders. In between these two extremes are polycrystalline aggregates, not randomly arranged but possessing some preferred orientation and this is the form taken by constructional materials, be they steel girders or the bones of a human or animal skeleton. The details of the preferred orientation determine the ability of the material to withstand stress in any direction. In the case of bone the crucial factor is the orientation of the c-axes of the mineral content - the crystals of the hexagonal hydroxyapatite - and this can readily be determined by neutron diffraction. In particular it can be measured over the volume of a piece of bone, utilizing distances ranging from 1mm to 10mm. The major practical problem is to avoid the intense incoherent scattering from the hydrogen in the accompanying collagen; this can best be achieved by heat-treatment and it is demonstrated that this does not affect the underlying apatite. These studies of bone give leading anatomical information on the life and activities of humans and animals - including, for example, the life history of the human femur, the locomotion of sheep, the fracture of the legs of racehorses and the life-styles of Neolithic tribes. We conclude that the material is placed economically in the bone to withstand the expected stresses of life and the environment. The experimental results are presented in terms of the magnitude of the 0002 apatite reflection. It so happens that for a random powder the 0002, 1121 reflections, which are neighboring lines in the powder pattern, are approximately equal in intensity. The latter reflection, being of manifold multiplicity, is scarcely affected by preferred orientation so that the numerical value of the 0002/1121 ratio serves quite accurately as a quantitative measure of the degree of orientation of the c-axes in any chosen direction for a sample of bone.

  1. Neutron anatomy

    International Nuclear Information System (INIS)

    Bacon, G.E.

    1994-01-01

    The familiar extremes of crystalline material are single-crystals and random powders. In between these two extremes are polycrystalline aggregates, not randomly arranged but possessing some preferred orientation and this is the form taken by constructional materials, be they steel girders or the bones of a human or animal skeleton. The details of the preferred orientation determine the ability of the material to withstand stress in any direction. In the case of bone the crucial factor is the orientation of the c-axes of the mineral content - the crystals of the hexagonal hydroxyapatite - and this can readily be determined by neutron diffraction. In particular it can be measured over the volume of a piece of bone, utilizing distances ranging from 1mm to 10mm. The major practical problem is to avoid the intense incoherent scattering from the hydrogen in the accompanying collagen; this can best be achieved by heat-treatment and it is demonstrated that this does not affect the underlying apatite. These studies of bone give leading anatomical information on the life and activities of humans and animals - including, for example, the life history of the human femur, the locomotion of sheep, the fracture of the legs of racehorses and the life-styles of Neolithic tribes. We conclude that the material is placed economically in the bone to withstand the expected stresses of life and the environment. The experimental results are presented in terms of the magnitude of the 0002 apatite reflection. It so happens that for a random powder the 0002, 1121 reflections, which are neighboring lines in the powder pattern, are approximately equal in intensity. The latter reflection, being of manifold multiplicity, is scarcely affected by preferred orientation so that the numerical value of the 0002/1121 ratio serves quite accurately as a quantitative measure of the degree of orientation of the c-axes in any chosen direction for a sample of bone

  2. Basics of Neutrons for First Responders

    Energy Technology Data Exchange (ETDEWEB)

    Rees, Brian G. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2018-02-05

    These are slides from a presentation on the basics of neutrons. A few topics covered are: common origins of terrestrial neutron radiation, neutron sources, neutron energy, interactions, detecting neutrons, gammas from neutron interactions, neutron signatures in gamma-ray spectra, neutrons and NaI, neutron fluence to dose (msV), instruments' response to neutrons.

  3. Forward to all-around survey of environmental neutrons from cosmic ray secondary neutron measurements. History and prospects

    International Nuclear Information System (INIS)

    Aratani, M.

    2000-01-01

    At the present stage of our civilization, environmental neutrons come from not only cosmic ray but also the various kinds of nuclear facilities where uranium, plutonium, californium-252, and other transuranium elements are treated in a large scale. To be regret, those neutron-emitting elements have already been released into the environment by experiments with the military purpose, and been distributed among atmosphere, hydrosphere and geosphere in further larger scale than the peaceful use of nuclear energy. Now environmental neutrons should be surveyed against the horizontal component from the nuclear facilities, upward component from soil, and downward component as secondary neutron from cosmic ray, which is to be regarded as background neutron in the environment. The third category of neutrons have long been surveyed by Y. Nishina and his group of the Institute of Physical and Chemical Research (IPCR) since 1970 at the Itabashi Branch (Itabashi, Tokyo) of IPCR. The BF 3 gas-filled monitors (20 cm in diameter x 200 cm) of 28 (36 at maximum) vessels were used for neutrons till Sept. of 1998, and were transferred to Yanpahchin, Tibet, China for the primary neutrons that might be preferred to secondary ones by researchers of the cosmic ray. A critical accident happened at the Tokai facilities of JCO (Japan Conversion Organization) on Sept. 30 1999, and was discussed in various contexts at home and in a severe tone abroad. A background survey of the environmental neutrons has not been made at any nuclear site or facilities concerning fission in this country. The neutron monitor which detected and recorded the neutrons from the JCO critical accidents was what had been equipped for the fusion research, but not for fission application. Radiation education on neutron has not been made in both school and social education. Basic scientists also may be responsible for the critical accident through making light of these fundamental aspects of nuclear technology. In this

  4. Internal strain measurement using pulsed neutron diffraction at LANSCE

    International Nuclear Information System (INIS)

    Goldstone, J.A.; Bourke, M.A.M.; Shi, N.

    1994-01-01

    The presence of residual stress in engineering components can effect their mechanical properties and structural integrity. Neutron diffraction in the only technique that can make nondestructive measurements in the interior of components. By recording the change in crystalline lattice spacings, elastic strains can be measured for individual lattice reflections. Using a pulsed neutron source, all lattice reflections are recorded in each measurement, which allows for easy examination of heterogeneous materials such as metal matrix composites. Measurements made at the Manuel Lujan Jr. Neutron Scattering Center (LANSCE) demonstrate the potential at pulsed sources for in-situ stress measurements at ambient and elevated temperatures

  5. Neutron radiography using neutron imaging plate

    International Nuclear Information System (INIS)

    Chankow, Nares; Wonglee, Sarinrat

    2008-01-01

    Full text: The aims of this research are to study properties of neutron imaging plate, to obtain a suitable condition for neutron radiography and to use the neutron imaging plate for testing of materials nondestructively. The experiments were carried out by using a neutron beam from the Thai Research Reactor TRR-1/M1 at a power of 1.2 MW. A BAS-ND 2040 FUJI neutron imaging plate and a MX125 Kodak X-ray film/Gadolinium neutron converter screen combination were tested for comparison. It was found that the photostimulated light (PSL) read out of the imaging plate was directly proportional to the exposure time. It was also found that radiography with neutron using the imaging plate was approximately 40 times faster than the conventional neutron radiography using x-ray film/Gd converter screen combination. The sensitivity of the imaging plate to gamma-rays was investigated by using gamma-rays from an 192 Ir and a 60 Co radiographic sources. The imaging plate was found to be 5-6 times less sensitive to gamma-rays than a FUJI BAS-MS 2040 gamma-ray imaging plate. Finally, some specimens were selected to be radiographed with neutrons using the imaging plate and the x-ray film/Gd converter screen combination in comparison to x-rays. Parts containing light elements could be clearly observed by the two neutron radiographic techniques. It could be concluded that the image quality from the neutron imaging plate was comparable to the conventional x-ray film/Gd converter screen combination but the exposure time could be approximately reduced by a factor of 40

  6. Single event upset and charge collection measurements using high energy protons and neutrons

    International Nuclear Information System (INIS)

    Normand, E.; Oberg, D.L.; Wert, J.L.; Ness, J.D.; Majewski, P.P.; Wender, S.; Gavron, A.

    1994-01-01

    RAMs, microcontrollers and surface barrier detectors were exposed to beams of high energy protons and neutrons to measure the induced number of upsets as well as energy deposition. The WNR facility at Los Alamos provided a neutron spectrum similar to that of the atmospheric neutrons. Its effect on devices was compared to that of protons with energies of 200, 400, 500, and 800 MeV. Measurements indicate that SEU cross sections for 400 MeV protons are similar to those induced by the atmospheric neutron spectrum

  7. Sources of polarized neutrons

    International Nuclear Information System (INIS)

    Walter, L.

    1983-01-01

    Various sources of polarized neutrons are reviewed. Monoenergetic source produced with unpolarized or polarized beams, white sources of polarized neutrons, production by transmissions through polarized hydrogen targets and polarized thermal neutronsare discussed, with appropriate applications included. (U.K.)

  8. Neutron delayed choice experiments

    International Nuclear Information System (INIS)

    Bernstein, H.J.

    1986-01-01

    Delayed choice experiments for neutrons can help extend the interpretation of quantum mechanical phenomena. They may also rule out alternative explanations which static interference experiments allow. A simple example of a feasible neutron test is presented and discussed. (orig.)

  9. Neutron radiation capture

    International Nuclear Information System (INIS)

    1986-01-01

    For all stable and experimentally studied radionuclides evaluated data are presented on cross sections of thermal neutrons, on resonance integrals and medium neutron cross sections with energy of 30 KeV. Refs, figs and tabs

  10. Neutron radiography in metallurgy

    International Nuclear Information System (INIS)

    Rant, J.; Ilic, R.

    1977-01-01

    The review surveys microneutronographic and neutron-induced autoradiographic techniques and their applications in metallurgy. A brief survey of applications of neutron radiography as a method of non-destructive testing to some macroscopic problems in metallurgy is included. (author)

  11. Atmospheric detritiation system performance

    International Nuclear Information System (INIS)

    Longhurst, G.R.; Jalbert, R.A.; Rossmassler, R.L.

    1989-01-01

    An investigation of the performance of atmospheric detritiation systems and of possible ways for improving their performance was undertaken. Small-scale experiments demonstrated that system performance is strongly dependent on catalyst bed temperature. That may be helped by addition of protium to the process gas stream, but added protium at constant temperature does not increase conversion to HTO. Collection of the HTO on dry sieve with residual HTO fraction of less than one part in 10/sup 7/ was observed. Ways suggested for improvement in collection of HTO on molecular sieve beds include adding H/sub 2/O to the stream entering the molecular sieve and premoistening of the sieve with H/sub 2/O. While these improvement schemes may reduce HTO emissions they increase the amount of tritiated waste that must be handled

  12. Atmospheric detritiation system performance

    International Nuclear Information System (INIS)

    Longhurst, G.R.; Jalbert, R.A.; Rossmassler, R.L.; Los Alamos National Lab., NM; Princeton Univ., NJ

    1988-01-01

    An investigation of the performance of atmospheric detritiation systems and of possible ways for improving their performance was undertaken. Small-scale experiments demonstrated that system performance is strongly dependent on catalyst bed temperature. That may be helped by addition of protium to the process gas stream, but added protium at constant temperature does not increase conversion to HTO. Collection of the HTO on dry sieve with residual HTO fraction of less than one part in 10 7 was observed. Ways suggested for improvement in collection of HTO on molecular sieve beds include adding H 2 O to the stream entering the molecular sieve and premoistening of the sieve with H 2 O. While these improvement schemes may reduce HTO emissions they increase the amount of tritiated waste that must be handled. 13 refs., 4 figs

  13. Applications of neutron irradiation

    International Nuclear Information System (INIS)

    Ito, Yasuo

    1999-01-01

    The present state of art of applications of neutron irradiation is overviewed taking neutron activation analysis, prompt gamma-ray analysis, fission/alpha track methods, boron neutron capture therapy as examples. What is common among them is that the technologies are nearly matured for wide use by non- nuclear scientists. But the environment around research reactors is not prospective. These applications should be encouraged by incorporating in the neutron science society. (author)

  14. Neutron beams for therapy

    International Nuclear Information System (INIS)

    Kuplenikov, Eh.L.; Dovbnya, A.N.; Telegin, Yu.N.; Tsymbal, V.A.; Kandybej, S.S.

    2011-01-01

    It was given the analysis and generalization of the study results carried out during some decades in many world countries on application of thermal, epithermal and fast neutrons for neutron, gamma-neutron and neutron-capture therapy. The main attention is focused on the practical application possibility of the accumulated experience for the base creation for medical research and the cancer patients effective treatment.

  15. Polarimetric neutron scattering

    International Nuclear Information System (INIS)

    Tasset, F.

    2001-01-01

    Polarimetric Neutron Scattering in introduced, both by, explaining methodological issues and the corresponding instrumental developments. After a short overview of neutron spin polarization and the neutron polarization 3d-vector a pictorial approach of the microscopic theory is used to show how a polarized beam interacts with lattice and magnetic Fourier components in a crystal. Examples are given of using Spherical Neutron Polarimetry (SNP) and the corresponding Cryopad polarimeter for the investigation of non-collinear magnetic structures. (R.P.)

  16. Reactor Neutron Sources

    International Nuclear Information System (INIS)

    Aksenov, V.L.

    1994-01-01

    The present status and the prospects for development of reactor neutron sources for neutron scattering research in the world are considered. The fields of application of neutron scattering relative to synchrotron radiation, the creation stages of reactors (steady state and pulsed) and their position in comparison with spallation neutron sources at present and in the foreseen future are discussed. (author). 15 refs.; 8 figs.; 3 tabs

  17. Properties of neutron sources

    International Nuclear Information System (INIS)

    1987-03-01

    The Conference presentations were divided into sessions devoted to the following topics: white neutron sources, primarily pulsed (6 papers); fast neutron fields (5 papers); Californium-252 prompt fission neutron spectra (14 papers); monoenergetic sources and filtered beams (11 papers); 14 MeV neutron sources (10 papers); selected special application (one paper); and a general interest session (4 papers). Individual abstracts were prepared separately for the papers

  18. Intense fusion neutron sources

    International Nuclear Information System (INIS)

    Kuteev, B. V.; Goncharov, P. R.; Sergeev, V. Yu.; Khripunov, V. I.

    2010-01-01

    The review describes physical principles underlying efficient production of free neutrons, up-to-date possibilities and prospects of creating fission and fusion neutron sources with intensities of 10 15 -10 21 neutrons/s, and schemes of production and application of neutrons in fusion-fission hybrid systems. The physical processes and parameters of high-temperature plasmas are considered at which optimal conditions for producing the largest number of fusion neutrons in systems with magnetic and inertial plasma confinement are achieved. The proposed plasma methods for neutron production are compared with other methods based on fusion reactions in nonplasma media, fission reactions, spallation, and muon catalysis. At present, intense neutron fluxes are mainly used in nanotechnology, biotechnology, material science, and military and fundamental research. In the near future (10-20 years), it will be possible to apply high-power neutron sources in fusion-fission hybrid systems for producing hydrogen, electric power, and technological heat, as well as for manufacturing synthetic nuclear fuel and closing the nuclear fuel cycle. Neutron sources with intensities approaching 10 20 neutrons/s may radically change the structure of power industry and considerably influence the fundamental and applied science and innovation technologies. Along with utilizing the energy produced in fusion reactions, the achievement of such high neutron intensities may stimulate wide application of subcritical fast nuclear reactors controlled by neutron sources. Superpower neutron sources will allow one to solve many problems of neutron diagnostics, monitor nano-and biological objects, and carry out radiation testing and modification of volumetric properties of materials at the industrial level. Such sources will considerably (up to 100 times) improve the accuracy of neutron physics experiments and will provide a better understanding of the structure of matter, including that of the neutron itself.

  19. Intense fusion neutron sources

    Science.gov (United States)

    Kuteev, B. V.; Goncharov, P. R.; Sergeev, V. Yu.; Khripunov, V. I.

    2010-04-01

    The review describes physical principles underlying efficient production of free neutrons, up-to-date possibilities and prospects of creating fission and fusion neutron sources with intensities of 1015-1021 neutrons/s, and schemes of production and application of neutrons in fusion-fission hybrid systems. The physical processes and parameters of high-temperature plasmas are considered at which optimal conditions for producing the largest number of fusion neutrons in systems with magnetic and inertial plasma confinement are achieved. The proposed plasma methods for neutron production are compared with other methods based on fusion reactions in nonplasma media, fission reactions, spallation, and muon catalysis. At present, intense neutron fluxes are mainly used in nanotechnology, biotechnology, material science, and military and fundamental research. In the near future (10-20 years), it will be possible to apply high-power neutron sources in fusion-fission hybrid systems for producing hydrogen, electric power, and technological heat, as well as for manufacturing synthetic nuclear fuel and closing the nuclear fuel cycle. Neutron sources with intensities approaching 1020 neutrons/s may radically change the structure of power industry and considerably influence the fundamental and applied science and innovation technologies. Along with utilizing the energy produced in fusion reactions, the achievement of such high neutron intensities may stimulate wide application of subcritical fast nuclear reactors controlled by neutron sources. Superpower neutron sources will allow one to solve many problems of neutron diagnostics, monitor nano-and biological objects, and carry out radiation testing and modification of volumetric properties of materials at the industrial level. Such sources will considerably (up to 100 times) improve the accuracy of neutron physics experiments and will provide a better understanding of the structure of matter, including that of the neutron itself.

  20. Polarized neutron spectrometer

    International Nuclear Information System (INIS)

    Abov, Yu.G.; Novitskij, V.V.; Alfimenkov, V.P.; Galinskij, E.M.; Mareev, Yu.D.; Pikel'ner, L.B.; Chernikov, A.N.; Lason', L.; Tsulaya, V.M.; Tsulaya, M.I.

    2000-01-01

    The polarized neutron spectrometer, intended for studying the interaction of polarized neutrons with nuclei and condensed media in the area of energies from thermal up to several electron-volt, is developed at the IBR-2 reactor (JINR, Dubna). Diffraction on the Co(92%)-Fe(8%) magnetized monocrystals is used for the neutron polarization and polarization analysis. The neutron polarization within the whole energy range equals ∼ 95% [ru

  1. Isotopic neutron sources for neutron activation analysis

    International Nuclear Information System (INIS)

    Hoste, J.

    1988-06-01

    This User's Manual is an attempt to provide for teaching and training purposes, a series of well thought out demonstrative experiments in neutron activation analysis based on the utilization of an isotopic neutron source. In some cases, these ideas can be applied to solve practical analytical problems. 19 refs, figs and tabs

  2. Workshop on polarized neutron filters and polarized pulsed neutron experiments

    International Nuclear Information System (INIS)

    Itoh, Shinichi

    2004-07-01

    The workshop was held in KEK by thirty-three participants on April 26, 2004. The polarized neutron filter method was only discussed. It consists of three parts; the first part was discussed on the polarized neutron methods, the second part on the polarized neutron experiments and the third on the pulse neutron spectrometer and polarized neutron experiments. The six papers were presented such as the polarized 3 He neutron spin filter, neutron polarization by proton polarized filter, soft master and neutron scattering, polarized neutron in solid physics, polarization experiments by chopper spectroscope and neutron polarization system in superHRPD. (S.Y.)

  3. Spallation neutron sources

    International Nuclear Information System (INIS)

    Fraser, J.S.; Bartholomew, G.A.

    1983-01-01

    The principles and theory of spallation neutron sources are outlined and a comparison is given with other types of neutron source. A summary of the available accelerator types for spallation neutron sources and their advantages and disadvantages is presented. Suitable target materials are discussed for specific applications, and typical target assemblies shown. (U.K.)

  4. Shielded regenerative neutron detector

    International Nuclear Information System (INIS)

    Terhune, J.H.; Neissel, J.P.

    1978-01-01

    An ion chamber type neutron detector is disclosed which has a greatly extended lifespan. The detector includes a fission chamber containing a mixture of active and breeding material and a neutron shielding material. The breeding and shielding materials are selected to have similar or substantially matching neutron capture cross-sections so that their individual effects on increased detector life are mutually enhanced

  5. Prototype Neutron Energy Spectrometer

    International Nuclear Information System (INIS)

    Mitchell, Stephen; Mukhopadhyay, Sanjoy; Maurer, Richard; Wolff, Ronald

    2010-01-01

    The project goals are: (1) Use three to five pressurized helium tubes with varying polyethylene moderators to build a neutron energy spectrometer that is most sensitive to the incident neutron energy of interest. Neutron energies that are of particular interest are those from the fission neutrons (typically around 1-2 MeV); (2) Neutron Source Identification - Use the neutron energy 'selectivity' property as a tool to discriminate against other competing processes by which neutrons are generated (viz. Cosmic ray induced neutron production (ship effect), (a, n) reactions); (3) Determine the efficiency as a function of neutron energy (response function) of each of the detectors, and thereby obtain the composite neutron energy spectrum from the detector count rates; and (4) Far-field data characterization and effectively discerning shielded fission source. Summary of the presentation is: (1) A light weight simple form factor compact neutron energy spectrometer ready to be used in maritime missions has been built; (2) Under laboratory conditions, individual Single Neutron Source Identification is possible within 30 minutes. (3) Sources belonging to the same type of origin viz., (a, n), fission, cosmic cluster in the same place in the 2-D plot shown; and (4) Isotopes belonging to the same source origin like Cm-Be, Am-Be (a, n) or Pu-239, U-235 (fission) do have some overlap in the 2-D plot.

  6. Prototype Neutron Energy Spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Stephen Mitchell, Sanjoy Mukhopadhyay, Richard Maurer, Ronald Wolff

    2010-06-16

    The project goals are: (1) Use three to five pressurized helium tubes with varying polyethylene moderators to build a neutron energy spectrometer that is most sensitive to the incident neutron energy of interest. Neutron energies that are of particular interest are those from the fission neutrons (typically around 1-2 MeV); (2) Neutron Source Identification - Use the neutron energy 'selectivity' property as a tool to discriminate against other competing processes by which neutrons are generated (viz. Cosmic ray induced neutron production [ship effect], [a, n] reactions); (3) Determine the efficiency as a function of neutron energy (response function) of each of the detectors, and thereby obtain the composite neutron energy spectrum from the detector count rates; and (4) Far-field data characterization and effectively discerning shielded fission source. Summary of the presentation is: (1) A light weight simple form factor compact neutron energy spectrometer ready to be used in maritime missions has been built; (2) Under laboratory conditions, individual Single Neutron Source Identification is possible within 30 minutes. (3) Sources belonging to the same type of origin viz., (a, n), fission, cosmic cluster in the same place in the 2-D plot shown; and (4) Isotopes belonging to the same source origin like Cm-Be, Am-Be (a, n) or Pu-239, U-235 (fission) do have some overlap in the 2-D plot.

  7. Thermal neutron polarisation

    International Nuclear Information System (INIS)

    Satya Murthy, N.S.; Madhava Rao, L.

    1984-01-01

    The basic principle for the production of polarised thermal neutrons is discussed and the choice of various crystal monochromators surveyed. Brief mention of broad-spectrum polarisers is made. The application of polarised neutrons to the study of magnetisation density distributions in magnetic crystals, the dynamic concept of polarisation, principle and use of polarisation analysis, the neutron spin-echo technique are discussed. (author)

  8. Fundamental neutron physics

    International Nuclear Information System (INIS)

    Deslattes, R.; Dombeck, T.; Greene, G.; Ramsey, N.; Rauch, H.; Werner, S.

    1984-01-01

    Fundamental physics experiments of merit can be conducted at the proposed intense neutron sources. Areas of interest include: neutron particle properties, neutron wave properties, and fundamental physics utilizing reactor produced γ-rays. Such experiments require intense, full-time utilization of a beam station for periods ranging from several months to a year or more

  9. Neutron detection and radiography

    International Nuclear Information System (INIS)

    Bollen, R.H.; Van Esch, R.F.

    1975-01-01

    An improved method of recording neutron images is described which comprises imagewise irradiating with neutrons an intensifying screen containing a gadolinium compound that fluoresces when struck by x-rays and subjecting the fluorescent light pattern resulting from the impact of the neutrons on the screen onto a photographic material. (auth)

  10. Neutron Scattering Software

    Science.gov (United States)

    Home Page | Facilities | Reference | Software | Conferences | Announcements | Mailing Lists Neutron Scattering Banner Neutron Scattering Software A new portal for neutron scattering has just been established sets KUPLOT: data plotting and fitting software ILL/TAS: Matlab probrams for analyzing triple axis data

  11. International Neutron Radiography Newsletter

    DEFF Research Database (Denmark)

    Domanus, Joseph Czeslaw

    1986-01-01

    At the First World Conference on Neutron Radiography i t was decided to continue the "Neutron Radiography Newsletter", published previously by J.P. Barton, as the "International Neutron Radiography Newsletter" (INRNL), with J.C. Doraanus as editor. The British Journal of Non-Destructive Testing...

  12. Polarized Neutron Scattering

    OpenAIRE

    Roessli, B.; Böni, P.

    2000-01-01

    The technique of polarized neutron scattering is reviewed with emphasis on applications. Many examples of the usefulness of the method in various fields of physics are given like the determination of spin density maps, measurement of complex magnetic structures with spherical neutron polarimetry, inelastic neutron scattering and separation of coherent and incoherent scattering with help of the generalized XYZ method.

  13. Stress measurement by neutron diffraction method. Standard method using angular dispersion method and trial of using neutron IP

    International Nuclear Information System (INIS)

    Sasaki, Toshihiko; Takago, Shigeki

    2016-01-01

    This paper outlined a stress measurement method using neutrons, and introduced the application examples to stress measurement for metal-based composite materials. In the angular dispersion type measurement using a steady-state reactor type neutron source, the white beams taken out from a nuclear reactor are monochromatized (wavelength λ is a constant value) with a single crystal monochromator and utilized. As an example of measurement, there was the case as follows: the stress of a sintered material which has been put to practical use as valve seat part for automobiles was measured by the neutron method, and the deformation behavior during load was studied. This study performed neutron diffraction measurement using a residual stress analyzer (RESA: Diffractometer for Residual Stress Analysis) installed at JAEA's experimental reactor JRR-3. As a result, it was found that the stress state of the sintered composite material of Fe-Cr and TiN can be predicted with a micromechanics model. A neutron diffraction ring can be obtained using a neutron image plate (IP), where fine powder of gadolinium (Gd) was incorporated into IP for X-rays, and it can be used as an IP reader in the same way as the case of X-rays. A report has been introduced on the examination results of the highly accurate stress measurement by applying the cos α method devised for X-ray stress measurement to neutron diffraction ring. (A.O.)

  14. Current Status and Future Works of Neutron Scattering Laboratory at BATAN in Serpong

    International Nuclear Information System (INIS)

    Ikram, A.

    2008-01-01

    Current status of neutron beam instruments using neutrons produced by the Multi Purpose Research Reactor--30MWth (MPR 30, RSG GA Siwabessy) located in Serpong is presented. Description of the reactor as the neutron source is mentioned briefly. There are six neutron beam tubes coming from the beryllium reflector surrounding half of the reactor core providing neutrons in the experimental hall of the reactor (XHR). Four of them are dedicated to R and D in materials science using neutron scattering techniques. Neutron Radiography Facility (NRF), Triple Axis Spectrometer (TAS) and Residual Stress Measurement (RSM) Diffractometer are installed respectively at beam tubes S2, S4 and S6. The largest neutron beam tube (S5) is exploited to accommodate two neutron guide tubes that transfer the neutrons to a neighbouring building called neutron guide hall (NGH). There are three other neutron beam instruments installed in this building, namely Small Angle Neutron Scattering (SANS) Spectrometer (SMARTer), High Resolution SANS (HRSANS) Spectrometer and High Resolution Powder Diffractometer (HRPD). In the XHR, a Four Circle and Texture Diffractometer (FCD/TD) is attached to one of the neutron guide tubes. These seven instruments were installed to utilize the neutrons for materials science research, and recently the RSM diffractometer has shown its capabilities in identifying different amount of stress left due to different treatments of welding in fuel cladding, while the SANS spectrometer is now gaining capabilities in identifying different sizes and shapes of macromolecules in polymers as well as investigations of magnetic samples. In the mean time, non-destructive tests using the NRF is gathering more confidence from some latest real time measurements eventhough there are still some shortcomings in the components and their alignments. Future works including improvement of each facility and its components, even replacement of some parts are necessary and have to be carried out

  15. Assessment of residual life of fast breeder test reactor

    International Nuclear Information System (INIS)

    Srinivasan, G.

    2016-01-01

    The Fast Breeder Test Reactor (FBTR) is a loop type sodium cooled fast reactor and has been in operation since 1985. As a part of regulatory requirement for relicensing, residual life assessment had to be carried out. The systems are made of SS 316, and designed for creep and fatigue. The design life for creep is 100,000 h at 550°C. The design fatigue cycle for operation from shutdown to full power varies from component to component. In general, most of the components are designed for 2000 cycles. The reactor has operated mostly below the design temperatures. It is seen that enough creep-fatigue life is available for the non-replaceable, permanent components. The residual life was found to be governed by the residual ductility of the Grid Plate supporting the core after neutron irradiation. Fast flux measurements were carried out at the grid plate location. Samples were irradiated and tensile tested. Results indicate the allowable dpa for a 10% residual ductility criterion as 4.37. This gave a residual life of ~ 6 Effective Full Power Years for the reactor as of Feb 2012. Measures to reduce the neutron dose on the grid plate are being taken. (author)

  16. Refractive neutron lens

    International Nuclear Information System (INIS)

    Petrov, P.V.; Kolchevsky, N.N.

    2013-01-01

    Model of the refractive neutron lens is proposed. System of N lenses acts as one thin lens with a complex refraction index n*. The maximum number N max of individual lenses for 'thick' neutron lens is calculated. Refractive neutron lens properties (resolution, focal depth) as function of resolution factor F 0 =ρbc/μ and depth of field factor dF 0 =λF 0 =λρbc/μ are calculated. It is shown that micro resolution of the refractive neutron optics is far from the wavelength in size and its open possibilities for progress in refractive neutron optics. (authors)

  17. Neutron scattering. Experiment manuals

    Energy Technology Data Exchange (ETDEWEB)

    Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner (eds.)

    2010-07-01

    The following topics are dealt with: The thermal triple axis spectrometer PUMA, the high-resolution powder diffractometer SPODI, the hot single-crystal diffractometer HEiDi for structure analysis with neutrons, the backscattering spectrometer SPHERES, neutron polarization analysis with tht time-of-flight spectrometer DNS, the neutron spin-echo spectrometer J-NSE, small-angle neutron scattering with the KWS-1 and KWS-2 diffractometers, the very-small-angle neutron scattering diffractrometer with focusing mirror KWS-3, the resonance spin-echo spectrometer RESEDA, the reflectometer TREFF, the time-of-flight spectrometer TOFTOF. (HSI)

  18. Activation neutron detector

    International Nuclear Information System (INIS)

    Ambardanishvili, T.S.; Kolomiitsev, M.A.; Zakharina, T.Y.; Dundua, V.J.; Chikhladze, N.V.

    1976-01-01

    An activation neutron detector made as a moulded and cured composition of a material capable of being neutron-activated is described. The material is selected from a group consisting of at least two chemical elements, a compound of at least two chemical elements and their mixture, each of the chemical elements and their mixture, each of the chemical elements being capable of interacting with neutrons to form radioactive isotopes having different radiation energies when disintegrating. The material capable of being neutron-activated is distributed throughout the volume of a polycondensation resin inert with respect to neutrons and capable of curing. 17 Claims, No Drawings

  19. High energy neutron dosimeter

    International Nuclear Information System (INIS)

    Rai, K.S.F.

    1994-01-01

    A device for measuring dose equivalents in neutron radiation fields is described. The device includes nested symmetrical hemispheres (forming spheres) of different neutron moderating materials that allow the measurement of dose equivalents from 0.025 eV to past 1 GeV. The layers of moderating material surround a spherical neutron counter. The neutron counter is connected by an electrical cable to an electrical sensing means which interprets the signal from the neutron counter in the center of the moderating spheres. The spherical shape of the device allows for accurate measurement of dose equivalents regardless of its positioning. 2 figures

  20. Pulse neutron logging technique

    International Nuclear Information System (INIS)

    Bespalov, D.F.; Dylyuk, A.A.

    1975-01-01

    A new method of neutron-burst logging is proposed, residing in irradiating rocks with fast neutron bursts and registering the integrated flux burst of thermal and/or epithermal neutrons, from the moment of its initiation to that of full absorption. The obtaained value is representative of the rock properties (porosity, hydrogen content). The integrated flux in a burst of thermal and epithermal neutrons can be measured both by way of activation of a reference sample of a known chemical composition during the neutron burst and by recording the radiation of induced activity of the sample within an interval between two bursts. The proposed method features high informative value, accuracy and efficiency

  1. Neutron scattering. Experiment manuals

    International Nuclear Information System (INIS)

    Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner

    2012-01-01

    The following topics are dealt with: The thermal triple-axis spectrometer PUMA, the high-resolution powder diffractometer SPODI, the hot single-crystal diffractometer HEiDi for structure analysis with neutrons, the backscattering spectrometer SPHERES, the neutron polarization analyzer DNS, the neutron spin-echo spectrometer J-NSE, the small-angle neutron diffractometers KWS-1/-2, the very-small-angle neutron diffractometer with focusing mirror KWS-3, the resonance spin-echo spectrometer RESEDA, the reflectometer TREFF, the time-of-flight spectrometer TOFTOF. (HSI)

  2. Neutron techniques in Safeguards

    International Nuclear Information System (INIS)

    Zucker, M.S.

    1982-01-01

    An essential part of Safeguards is the ability to quantitatively and nondestructively assay those materials with special neutron-interactive properties involved in nuclear industrial or military technology. Neutron techniques have furnished most of the important ways of assaying such materials, which is no surprise since the neutronic properties are what characterizes them. The techniques employed rely on a wide selection of the many methods of neutron generation, detection, and data analysis that have been developed for neutron physics and nuclear science in general

  3. Nanosecond neutron generator

    International Nuclear Information System (INIS)

    Lobov, S.I.; Pavlovskaya, N.G.; Pukhov, S.P.

    1991-01-01

    High-voltage nanosecond neutron generator for obtaining neutrons in D-T reaction is described. Yield of 6x10 6 neutron/pulse was generated in a sealed gas-filled diode with a target on the cathode by accelerating pulse voltage of approximately 0.5 MV and length at half-height of 0.5 ns and deuterium pressure of 6x10 -2 Torr. Ways of increasing neutron yield and possibilities of creating generators of nanosecond neutron pulses with great service life are considered

  4. Principles of neutron reflection

    International Nuclear Information System (INIS)

    Felcher, G.P.

    1988-08-01

    Neutron reflection is perhaps the most developed branch of slow neutrons optics, which in itself is a direct consequence of the undulatory nature of the neutron. After reviewing the basic types of interactions (nuclear and magnetic) between neutrons and matter, the formalism is introduced to calculate the reflectivity from a sample composed of stacked flat layers and, inversely, to calculate the stacking from reflectivity measurements. Finally, a brief survey of the applications of neutron reflection is given, both in technology and in fundamental research. 32 refs., 6 figs

  5. Grazing Incidence Neutron Optics

    Science.gov (United States)

    Gubarev, Mikhail V. (Inventor); Ramsey, Brian D. (Inventor); Engelhaupt, Darell E. (Inventor)

    2013-01-01

    Neutron optics based on the two-reflection geometries are capable of controlling beams of long wavelength neutrons with low angular divergence. The preferred mirror fabrication technique is a replication process with electroform nickel replication process being preferable. In the preliminary demonstration test an electroform nickel optics gave the neutron current density gain at the focal spot of the mirror at least 8 for neutron wavelengths in the range from 6 to 20.ANG.. The replication techniques can be also be used to fabricate neutron beam controlling guides.

  6. Neutron scattering. Experiment manuals

    International Nuclear Information System (INIS)

    Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner

    2010-01-01

    The following topics are dealt with: The thermal triple axis spectrometer PUMA, the high-resolution powder diffractometer SPODI, the hot single-crystal diffractometer HEiDi for structure analysis with neutrons, the backscattering spectrometer SPHERES, neutron polarization analysis with tht time-of-flight spectrometer DNS, the neutron spin-echo spectrometer J-NSE, small-angle neutron scattering with the KWS-1 and KWS-2 diffractometers, the very-small-angle neutron scattering diffractrometer with focusing mirror KWS-3, the resonance spin-echo spectrometer RESEDA, the reflectometer TREFF, the time-of-flight spectrometer TOFTOF. (HSI)

  7. Management of NORM Residues

    International Nuclear Information System (INIS)

    2013-06-01

    The IAEA attaches great importance to the dissemination of information that can assist Member States in the development, implementation, maintenance and continuous improvement of systems, programmes and activities that support the nuclear fuel cycle and nuclear applications, and that address the legacy of past practices and accidents. However, radioactive residues are found not only in nuclear fuel cycle activities, but also in a range of other industrial activities, including: - Mining and milling of metalliferous and non-metallic ores; - Production of non-nuclear fuels, including coal, oil and gas; - Extraction and purification of water (e.g. in the generation of geothermal energy, as drinking and industrial process water; in paper and pulp manufacturing processes); - Production of industrial minerals, including phosphate, clay and building materials; - Use of radionuclides, such as thorium, for properties other than their radioactivity. Naturally occurring radioactive material (NORM) may lead to exposures at some stage of these processes and in the use or reuse of products, residues or wastes. Several IAEA publications address NORM issues with a special focus on some of the more relevant industrial operations. This publication attempts to provide guidance on managing residues arising from different NORM type industries, and on pertinent residue management strategies and technologies, to help Member States gain perspectives on the management of NORM residues

  8. Evaluation of the Neutron Detector Response for Cosmic Ray Energy Spectrum by Monte Carlo Transport Simulation

    International Nuclear Information System (INIS)

    Pazianotto, Mauricio T.; Carlson, Brett V.; Federico, Claudio A.; Gonzalez, Odair L.

    2011-01-01

    Neutrons generated by the interaction of cosmic rays with the atmosphere make an important contribution to the dose accumulated in electronic circuits and aircraft crew members at flight altitude. High-energy neutrons are produced in spallation reactions and intranuclear cascade processes by primary cosmic-ray particle interactions with atoms in the atmosphere. These neutrons can produce secondary neutrons and also undergo a moderation process due to atmosphere interactions, resulting in a wider energy spectrum, ranging from thermal energies (0.025 eV) to energies of several hundreds of MeV. The Long-Counter (LC) detector is a widely used neutron detector designed to measure the directional flux of neutrons with about constant response over a wide energy range (thermal to 20 MeV). ). Its calibration process and the determination of its energy response for the wide-energy of cosmic ray induced neutron spectrum is a very difficult process due to the lack of installations with these capabilities. The goal of this study is to assess the behavior of the response of a Long Counter using the Monte Carlo (MC) computational code MCNPX (Monte Carlo N-Particle eXtended). The dependence of the Long Counter response on the angle of incidence, as well as on the neutron energy, will be carefully investigated, compared with the experimental data previously obtained with 241 Am-Be and 252 Cf neutron sources and extended to the neutron spectrum produced by cosmic rays. (Author)

  9. Effect of residual stress on the integrity of a branch connection

    International Nuclear Information System (INIS)

    Law, M.; Kirstein, O.; Luzin, V.

    2012-01-01

    A new connection to an existing gas pipeline was made by hot-tapping, welding directly onto a pressurised pipeline. The welds were not post-weld heat treated, causing significant residual stresses. The critical weld had residual stresses determined by neutron diffraction using ANSTO's residual stress diffractometer, Kowari. The maximum measured residual stress (290 MPa) was 60% of the yield strength. The magnitudes of errors from a number of sources were estimated. An integrity assessment of the welded branch connection was performed with the measured residual stress values and with residual stress distributions from the BS 7910 and API 579 analysis codes. Analysis using estimates of residual stress from API 579 overestimated the critical crack size. Highlights: ► Residual stresses were measured by neutron diffraction in a thick section, non post-weld heat treated ferritic weld. ► There is little published data on these welds. ► The work compares the measured residual stresses with code-based residual stress distributions.

  10. Thermal neutron moderating device

    International Nuclear Information System (INIS)

    Takigami, Hiroyuki.

    1995-01-01

    In a thermal neutron moderating device, superconductive coils for generating magnetic fields capable of applying magnetic fields vertical to the longitudinal direction of a thermal neutron passing tube, and superconductive coils for magnetic field gradient for causing magnetic field gradient in the longitudinal direction of the thermal neutron passing tube are disposed being stacked at the outside of the thermal neutron passing tube. When magnetic field gradient is present vertically to the direction of a magnetic moment, thermal neutrons undergo forces in the direction of the magnetic field gradient in proportion to the magnetic moment. Then, the magnetic moment of the thermal neutrons is aligned with the direction vertical to the passing direction of the thermal neutrons, to cause the magnetic field gradient in the passing direction of the thermal neutrons. The speed of the thermal neutrons can be optionally selected and the wavelength can freely be changed by applying forces to the thermal neutrons and changing the extent and direction of the magnetic field gradient. Superconductive coils are used as the coils for generating magnetic fields and the magnetic field gradient in order to change extremely high energy of the thermal neutrons. (N.H.)

  11. Atlas of neutron resonances

    CERN Document Server

    Mughabghab, Said

    2018-01-01

    Atlas of Neutron Resonances: Resonance Properties and Thermal Cross Sections Z= 1-60, Sixth Edition, contains an extensive list of detailed individual neutron resonance parameters for Z=1-60, as well as thermal cross sections, capture resonance integrals, average resonance parameters and a short survey of the physics of thermal and resonance neutrons. The long introduction contains: nuclear physics formulas aimed at neutron physicists; topics of special interest such as valence neutron capture, nuclear level density parameters, and s-, p-, and d-wave neutron strength functions; and various comparisons of measured quantities with the predictions of nuclear models, such as the optical model. As in the last edition, additional features have been added to appeal to a wider spectrum of users. These include: spin-dependent scattering lengths that are of interest to solid-state physicists, nuclear physicists and neutron evaluators; calculated and measured Maxwellian average 5-keV and 30-keV capture cross sections o...

  12. Neutron image intensifier tubes

    International Nuclear Information System (INIS)

    Verat, M.; Rougeot, H.; Driard, B.

    1983-01-01

    The most frequently used techniques in neutron radiography employ a neutron converter consisting of either a scintillator or a thin metal sheet. The radiation created by the neutrons exposes a photographic film that is in contact with the converter: in the direct method, the film is exposed during the time that the object is irradiated with neutrons; in the transfer method, the film is exposed after the irradiation of the object with neutrons. In industrial non-destructive testing, when many identical objects have to be checked, these techniques have several disadvantages. Non-destructive testing systems without these disadvantages can be constructed around neutron-image intensifier tubes. A description and the operating characteristics of neutron-image intensifier tubes are given. (Auth.)

  13. Methods of neutron spectrometry

    International Nuclear Information System (INIS)

    Doerschel, B.

    1981-01-01

    The different methods of neutron spectrometry are based on the direct measurement of neutron velocity or on the use of suitable energy-dependent interaction processes. In the latter case the measuring effect of a detector is connected with the searched neutron spectrum by an integral equation. The solution needs suitable unfolding procedures. The most important methods of neutron spectrometry are the time-of-flight method, the crystal spectrometry, the neutron spectrometry by use of elastic collisions with hydrogen nuclei, and neutron spectrometry with the aid of nuclear reactions, especially of the neutron-induced activation. The advantages and disadvantages of these methods are contrasted considering the resolution, the measurable energy range, the sensitivity, and the experimental and computational efforts. (author)

  14. Neutrons as a probe

    International Nuclear Information System (INIS)

    Iizumi, Masashi

    1993-01-01

    As an introduction to the symposium a brief overview will be given about the features of neutrons as a probe. First it will be pointed out that the utilization of neutrons as a probe for investigating the structural and dynamical properties of condensed matters is a benign gift eventuated from the release of atomic energy initiated by Enrico Fermi exactly half century ago. Features of neutrons as a probe are discussed in accordance with the four basic physical properties of neutrons as an elementary particle; (1) no electric charge (the interaction with matter is nuclear), (2) the mass of neutron is 1 amu, (3) spin is 1/2 and (4) neutrons have magnetic dipole moment. Overview will be given on the uniqueness of neutrons as a probe and on the variety in the way they are used in the wide research area from the pure science to the industrial applications. (author)

  15. Neutron response study

    International Nuclear Information System (INIS)

    Endres, G.W.R.; Fix, J.J.; Thorson, M.R.; Nichols, L.L.

    1981-01-01

    Neutron response of the albedo type dosimeter is strongly dependent on the energy of the incident neutrons as well as the moderating material on the backside of the dosimeter. This study characterizes the response of the Hanford dosimeter for a variety of neutron energies for both a water and Rando phantom (a simulated human body consisting of an actual human skeleton with plastic for body muscles and certain organs). The Hanford dosimeter response to neutrons of different energies is typical of albedo type dosimeters. An approximate two orders of magnitude difference in response is observed between neutron energies of 100 keV and 10 MeV. Methods were described to compensate for the difference in dosimeter response between a laboratory neutron spectrum and the different spectra encountered at various facilities in the field. Generally, substantial field support is necessary for accurate neutron dosimetry

  16. Neutron structural biology

    Energy Technology Data Exchange (ETDEWEB)

    Niimura, Nobuo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-03-01

    Neutron diffraction provides an experimental method of directly locating hydrogen atoms in protein which play important roles in physiological functions. However, there are relatively few examples of neutron crystallography in biology since it takes a lot of time to collect a sufficient number of Bragg reflections due to the low flux of neutrons illuminating the sample. In order to overcome the flux problem, we have successfully developed the neutron IP, where the neutron converter, {sup 6}Li or Gd, was mixed with a photostimulated luminescence material on flexible plastic support. Neutron Laue diffraction 2A data from tetragonal lysozyme were collected for 10 days with neutron imaging plates, and 960 hydrogen atoms in the molecule and 157 bound water molecules were identified. These results explain the proposed hydrolysis mechanism of the sugar by the lysozyme molecule and that lysozyme is less active at pH7.0. (author)

  17. Using MCNP code for neutron and photon skyshine analysis

    Energy Technology Data Exchange (ETDEWEB)

    Zharkov, V.P.; Dikareva, O.F.; Kartashev, I.A.; Kiselev, A.N.; Netecha, M.E. [Research and Development Inst. of Power Engineering, Moscow (Russian Federation); Nomura, Y.; Tsubosaka, A. [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan)

    2000-03-01

    The MCNP Monte-Carlo code was used for the investigation of the sensitivity of neutron and neutron-induced secondary photon dose rate, total and thermal neutron fluxes and space-energy distributions to energy and angular distribution of radiation source, to thickness and composition of the ground, air density (including it changing with height), humidities of air and ground, thermalization effects, detector's dimension and its disposal above the ground level. The calculations were performed with the assumption that the source or released radiation into the atmosphere can be treated as a point source and the source containment structure has a negligible perturbation on the skyshine radiation field. (author)

  18. Matter and Radiation in Strong Magnetic Fields of Neutron Stars

    International Nuclear Information System (INIS)

    Lai, D

    2006-01-01

    Neutron stars are found to possess magnetic fields ranging from 10 8 G to 10 15 G, much larger than achievable in terrestrial laboratories. Understanding the properties of matter and radiative transfer in strong magnetic fields is essential for the proper interpretation of various observations of magnetic neutron stars, including radio pulsars and magnetars. This paper reviews the atomic/molecular physics and condensed matter physics in strong magnetic fields, as well as recent works on modeling radiation from magnetized neutron star atmospheres/surface layers

  19. Modeling the National Ignition Facility neutron imaging system.

    Science.gov (United States)

    Wilson, D C; Grim, G P; Tregillis, I L; Wilke, M D; Patel, M V; Sepke, S M; Morgan, G L; Hatarik, R; Loomis, E N; Wilde, C H; Oertel, J A; Fatherley, V E; Clark, D D; Fittinghoff, D N; Bower, D E; Schmitt, M J; Marinak, M M; Munro, D H; Merrill, F E; Moran, M J; Wang, T-S F; Danly, C R; Hilko, R A; Batha, S H; Frank, M; Buckles, R

    2010-10-01

    Numerical modeling of the neutron imaging system for the National Ignition Facility (NIF), forward from calculated target neutron emission to a camera image, will guide both the reduction of data and the future development of the system. Located 28 m from target chamber center, the system can produce two images at different neutron energies by gating on neutron arrival time. The brighter image, using neutrons near 14 MeV, reflects the size and symmetry of the implosion "hot spot." A second image in scattered neutrons, 10-12 MeV, reflects the size and symmetry of colder, denser fuel, but with only ∼1%-7% of the neutrons. A misalignment of the pinhole assembly up to ±175 μm is covered by a set of 37 subapertures with different pointings. The model includes the variability of the pinhole point spread function across the field of view. Omega experiments provided absolute calibration, scintillator spatial broadening, and the level of residual light in the down-scattered image from the primary neutrons. Application of the model to light decay measurements of EJ399, BC422, BCF99-55, Xylene, DPAC-30, and Liquid A suggests that DPAC-30 and Liquid A would be preferred over the BCF99-55 scintillator chosen for the first NIF system, if they could be fabricated into detectors with sufficient resolution.

  20. Neutron transportation simulator

    International Nuclear Information System (INIS)

    Uenohara, Yuzo.

    1995-01-01

    In the present invention, problems in an existent parallelized monte carlo method is solved, and behaviors of neutrons in a large scaled system are accurately simulated at a high speed. Namely, a neutron transportation simulator according to the monte carlo method simulates movement of each of neutrons by using a parallel computer. In this case, the system to be processed is divided based on a space region and an energy region to which neutrons belong. Simulation of neutrons in the divided regions is allotted to each of performing devices of the parallel computer. Tarry data and nuclear data of the neutrons in each of the regions are memorized dispersedly to memories of each of the performing devices. A transmission means for simulating the behaviors of the neutrons in the region by each of the performing devices, as well as transmitting the information of the neutrons, when the neutrons are moved to other region, to the performing device in a transported portion are disposed to each of the performing devices. With such procedures, simulation for the neutrons in the allotted region can be conducted with small capacity of memories. (I.S.)

  1. Instrumentation with polarized neutrons

    International Nuclear Information System (INIS)

    Boeni, P.; Muenzer, W.; Ostermann, A.

    2009-01-01

    Neutron scattering with polarization analysis is an indispensable tool for the investigation of novel materials exhibiting electronic, magnetic, and orbital degrees of freedom. In addition, polarized neutrons are necessary for neutron spin precession techniques that path the way to obtain extremely high resolution in space and time. Last but not least, polarized neutrons are being used for fundamental studies as well as very recently for neutron imaging. Many years ago, neutron beam lines were simply adapted for polarized beam applications by adding polarizing elements leading usually to unacceptable losses in neutron intensity. Recently, an increasing number of beam lines are designed such that an optimum use of polarized neutrons is facilitated. In addition, marked progress has been obtained in the technology of 3 He polarizers and the reflectivity of large-m supermirrors. Therefore, if properly designed, only factors of approximately 2-3 in neutron intensity are lost. It is shown that S-benders provide neutron beams with an almost wavelength independent polarization. Using twin cavities, polarized beams with a homogeneous phase space and P>0.99 can be produced without significantly sacrificing intensity. It is argued that elliptic guides, which are coated with large m polarizing supermirrors, provide the highest flux.

  2. Neutron wave optics studied with ultracold neutrons

    International Nuclear Information System (INIS)

    Steyerl, A.

    1984-01-01

    The author discusses experiments demonstrating or utilizing the wave properties of neutrons with wavelengths of about 100 nm. In particular the 'UCN gravity diffractometer' and the gravity spectrometer NESSIE (Neutronen-Schwerkraft-Spectrometrie) are illustrated. (Auth.)

  3. Neutron Optics: Towards Applications for Hot Neutrons

    International Nuclear Information System (INIS)

    Schanzer, C; Schneider, M; Böni, P

    2016-01-01

    Supermirrors with large critical angles of reflection, i.e. large index m are an essential ingredient to transport, focus and polarise neutrons over a wide range of energy. Here we summarise the recent developments of supermirror with very large critical angles of reflection and high reflectivity that were conducted at SwissNeutronics as well as their implementation in devices. Approaching critical angles m = 8 times the critical angle of natural nickel makes new applications possible and extends the use of reflection optics towards the regime of hot and epithermal neutrons. Based on comparisons of simulations with experiment we demonstrate future possibilities of applications of large-m supermirrors towards devices for neutrons with short wavelength. (paper)

  4. A polarizing neutron periscope for neutron imaging

    International Nuclear Information System (INIS)

    Schulz, Michael; Boeni, Peter; Calzada, Elbio; Muehlbauer, Martin; Neubauer, Andreas; Schillinger, Burkhard

    2009-01-01

    Optical neutron polarizers like guides or benders destroy the collimation of a neutron beam due to multiple reflections or scattering. This makes them unsuitable for their use in polarized neutron radiography, because the beam collimation is essential to obtain high spatial resolution. We have developed a neutron polarizer based on the principle of an optical periscope with a zigzag double reflection on two parallel high-m supermirror polarizers. If the supermirrors are perfectly parallel and flat, the beam collimation is left unchanged by such a device. A first proof of concept version of this type of polarizer was built and tested. We expect to achieve a beam polarization of up to 99% with an improved version yet to be built.

  5. Designing with residual materials

    NARCIS (Netherlands)

    Walhout, W.; Wever, R.; Blom, E.; Addink-Dölle, L.; Tempelman, E.

    2013-01-01

    Many entrepreneurial businesses have attempted to create value based on the residual material streams of third parties. Based on ‘waste’ materials they designed products, around which they built their company. Such activities have the potential to yield sustainable products. Many of such companies

  6. Residual stresses in zircaloy welds

    International Nuclear Information System (INIS)

    Santisteban, J. R.; Fernandez, L; Vizcaino, P.; Banchik, A.D.; Samper, R; Martinez, R. L; Almer, J; Motta, A.T.; Colas, K.B; Kerr, M.; Daymond, M.R

    2009-01-01

    Welds in Zirconium-based alloys are susceptible to hydrogen embrittlement, as H enters the material due to dissociation of water. The yield strain for hydride cracking has a complex dependence on H concentration, stress state and texture. The large thermal gradients produced by the applied heat; drastically changes the texture of the material in the heat affected zone, enhancing the susceptibility to delayed hydride cracking. Normally hydrides tend to form as platelets that are parallel to the normal direction, but when welding plates, hydride platelets may form on cooling with their planes parallel to the weld and through the thickness of the plates. If, in addition to this there are significant tensile stresses, the susceptibility of the heat affected zone to delayed hydride cracking will be increased. Here we have measured the macroscopic and microscopic residual stressed that appear after PLASMA welding of two 6mm thick Zircaloy-4 plates. The measurements were based on neutron and synchrotron diffraction experiments performed at the Isis Facility, UK, and at Advanced Photon Source, USA, respectively. The experiments allowed assessing the effect of a post-weld heat treatment consisting of a steady increase in temperature from room temperature to 450oC over a period of 4.5 hours; followed by cooling with an equivalent cooling rate. Peak tensile stresses of (175± 10) MPa along the longitudinal direction were found in the as-welded specimen, which were moderately reduced to (150±10) MPa after the heat-treatment. The parent material showed intergranular stresses of (56±4) MPa, which disappeared on entering the heat-affected zone. In-situ experiments during themal cyclong of the material showed that these intergranular stresses result from the anisotropy of the thermal expansion coefficient of the hexagonal crystal lattice. [es

  7. DIANE stationary neutron radiography system image quality and industrial applications

    International Nuclear Information System (INIS)

    Cluzeau, S.; Huet, J.; Tourneur, P. le

    1994-01-01

    The SODERN neutron radiography laboratory has operated since February 1993 using a sealed tube generator (GENIE 46). An experimental programme of characterization (dosimetry, spectroscopy) has confirmed the expected performances concerning: neutron flux intensity, neutron energy range, residual gamma flux. Results are given in a specific report [2]. This paper is devoted to the image performance reporting. ASTM and specific indicators have been used to test the image quality with various converters and films. The corresponding modulation transfer functions are to be determined from image processing. Some industrial applications have demonstrated the capabilities of the system: corrosion detection in aircraft parts, ammunitions filling testing, detection of polymer lacks in sandwich steel sheets, detection of moisture in a probe for geophysics, residual ceramic cores imaging in turbine blades. Various computerized electronic imaging systems will be tested to improve the industrial capabilities. (orig.)

  8. Simulation of a high energy neutron irradiation facility at beamline 11 of the China Spallation Neutron Source

    Energy Technology Data Exchange (ETDEWEB)

    Tairan, Liang [School of Physics and Electronic Information Inner Mongolia University for the Nationalities, Tongliao 028043 (China); Zhiduo, Li [Dongguan Branch, Institute of High Energy Physics, CAS, Beijing 100049 (China); Wen, Yin, E-mail: wenyin@aphy.iphy.ac.cn [Dongguan Branch, Institute of High Energy Physics, CAS, Beijing 100049 (China); Institute of Physics, CAS, P.O. Box 603, Beijing 100190 (China); Fei, Shen [Dongguan Branch, Institute of High Energy Physics, CAS, Beijing 100049 (China); Quanzhi, Yu [Dongguan Branch, Institute of High Energy Physics, CAS, Beijing 100049 (China); Institute of Physics, CAS, P.O. Box 603, Beijing 100190 (China); Tianjiao, Liang [Dongguan Branch, Institute of High Energy Physics, CAS, Beijing 100049 (China)

    2017-07-11

    The China Spallation Neutron Source (CSNS) will accommodate 20 neutron beamlines at its first target station. These beamlines serve different purposes, and beamline 11 is designed to analyze the degraded models and damage mechanisms, such as Single Event Effects in electronic components and devices for aerospace electronic systems. This paper gives a preliminary discussion on the scheme of a high energy neutron irradiation experiment at the beamline 11 shutter based on the Monte Carlo simulation method. The neutron source term is generated by calculating the neutrons scattering into beamline 11 with a model that includes the target-moderator-reflector area. Then, the neutron spectrum at the sample position is obtained. The intensity of neutrons with energy of hundreds of MeV is approximately 1E8 neutron/cm{sup 2}/s, which is useful for experiments. The displacement production rate and gas productions are calculated for common materials such as tungsten, tantalum and SS316. The results indicate that the experiment can provide irradiation dose rate ranges from 1E-5 to 1E-4 dpa per operating year. The residual radioactivity is also calculated for regular maintenance work. These results give the basic reference for the experimental design.

  9. Pulsed neutron porosity logging system

    International Nuclear Information System (INIS)

    Smith, H.D. Jr.; Smith, M.P.; Schultz, W.E.

    1978-01-01

    An improved pulsed neutron porosity logging system is provided in the present invention. A logging tool provided with a 14 MeV pulsed neutron source, an epithermal neutron detector, and a fast neutron detector is moved through a borehole. Repetitive bursts of neutrons irradiate the earth formations and, during the bursts, the fast neutron population is sampled. During the interval between bursts the epithermal neutron population is sampled along with background gamma radiation due to lingering thermal neutrons. The fast and epithermal neutron population measurements are combined to provide a measurement of formation porosity

  10. Bouncing neutrons and the neutron centrifuge

    International Nuclear Information System (INIS)

    Watson, P J S

    2003-01-01

    The recent observation of the quantum state of the neutron bouncing freely under gravity allows some novel experiments. A possible method of purifying the ground state is given. We investigate two possible applications. It appears that the state could not be used to set better limits on the electric dipole moment of the neutron. However, it would be possible to use the state to set limits on modifications of gravity at short distances

  11. Status of spallation neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Oyama, Yukio [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-03-01

    Existing and planned facilities using proton accelerator driven spallation neutron source are reviewed. These include new project of neutron science proposed from Japan Atomic Energy Research Institute. The present status of facility requirement and accelerator technology leads us to new era of neutron science such as neutron scattering research and nuclear transmutation study using very intense neutron source. (author)

  12. Neutron probe measurement of soil water content close to soil surface

    International Nuclear Information System (INIS)

    Faleiros, M.C.; Ravelo S, A.; Souza, M.D. de

    1993-01-01

    The problem of neutron probe soil water content measurements close to soil surface is analysed from the spatial variability and also from the slow neutron loss to the atmosphere points of view. Results obtained on a dark red latosol of the county of Piracicaba, SP, indicate the possibility of precisely measuring the neutron sphere of influence when different media are used on soil surface. (author). 7 refs, 5 figs, 1 tab

  13. Prototype Stilbene Neutron Collar

    Energy Technology Data Exchange (ETDEWEB)

    Prasad, M. K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Shumaker, D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Snyderman, N. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Verbeke, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Wong, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-10-26

    A neutron collar using stilbene organic scintillator cells for fast neutron counting is described for the assay of fresh low enriched uranium (LEU) fuel assemblies. The prototype stilbene collar has a form factor similar to standard He-3 based collars and uses an AmLi interrogation neutron source. This report describes the simulation of list mode neutron correlation data on various fuel assemblies including some with neutron absorbers (burnable Gd poisons). Calibration curves (doubles vs 235U linear mass density) are presented for both thermal and fast (with Cd lining) modes of operation. It is shown that the stilbene collar meets or exceeds the current capabilities of He-3 based neutron collars. A self-consistent assay methodology, uniquely suited to the stilbene collar, using triples is described which complements traditional assay based on doubles calibration curves.

  14. Biological effects of neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Ogiu, Toshiaki; Ohmachi, Yasushi; Ishida, Yuka [National Inst. of Radiological Sciences, Chiba (JP)] [and others

    2003-03-01

    Although the occasion to be exposed to neutrons is rare in our life, except for nuclear accidents like in the critical accident at Tokai-mura in 1999, countermeasures against accident should be always prepared. In the Tokai-mura accident, residents received less than 21 mSv of neutrons and gamma rays. The cancer risks and fetal effects of low doses of neutrons were matters of concern among residents. The purpose of this program is to investigate the relative biological effectiveness (RBE) for leukemias, and thereby to assess risks of neutrons. Animal experiments are planed to obtain the following RBEs: (1) RBE for the induction of leukemias in mice and (2) RBE for effects on fetuses. Cyclotron fast neutrons (10 MeV) and electrostatic accelerator-derived neutrons (2 MeV) are used for exposure in this program. Furthermore, cytological and cytogenetic analyses will be performed. (author)

  15. Neutron sources and applications

    Energy Technology Data Exchange (ETDEWEB)

    Price, D.L. [ed.] [Argonne National Lab., IL (United States); Rush, J.J. [ed.] [National Inst. of Standards and Technology, Gaithersburg, MD (United States)

    1994-01-01

    Review of Neutron Sources and Applications was held at Oak Brook, Illinois, during September 8--10, 1992. This review involved some 70 national and international experts in different areas of neutron research, sources, and applications. Separate working groups were asked to (1) review the current status of advanced research reactors and spallation sources; and (2) provide an update on scientific, technological, and medical applications, including neutron scattering research in a number of disciplines, isotope production, materials irradiation, and other important uses of neutron sources such as materials analysis and fundamental neutron physics. This report summarizes the findings and conclusions of the different working groups involved in the review, and contains some of the best current expertise on neutron sources and applications.

  16. Neutron sources and applications

    International Nuclear Information System (INIS)

    Price, D.L.; Rush, J.J.

    1994-01-01

    Review of Neutron Sources and Applications was held at Oak Brook, Illinois, during September 8--10, 1992. This review involved some 70 national and international experts in different areas of neutron research, sources, and applications. Separate working groups were asked to (1) review the current status of advanced research reactors and spallation sources; and (2) provide an update on scientific, technological, and medical applications, including neutron scattering research in a number of disciplines, isotope production, materials irradiation, and other important uses of neutron sources such as materials analysis and fundamental neutron physics. This report summarizes the findings and conclusions of the different working groups involved in the review, and contains some of the best current expertise on neutron sources and applications

  17. Neutron scattering and magnetism

    International Nuclear Information System (INIS)

    Mackintosh, A.R.

    1983-01-01

    Those properties of the neutron which make it a unique tool for the study of magnetism are described. The scattering of neutrons by magnetic solids is briefly reviewed, with emphasis on the information on the magnetic structure and dynamics which is inherent in the scattering cross-section. The contribution of neutron scattering to our understanding of magnetic ordering, excitations and phase transitions is illustrated by experimental results on a variety of magnetic crystals. (author)

  18. The Advanced Neutron Source

    International Nuclear Information System (INIS)

    Hayter, J.B.

    1989-01-01

    The Advanced Neutron Source (ANS) is a new user experimental facility planned to be operational at Oak Ridge in the late 1990's. The centerpiece of the ANS will be a steady-state research reactor of unprecedented thermal neutron flux (φ th ∼ 9·10 19 m -2 ·s -1 ) accompanied by extensive and comprehensive equipment and facilities for neutron-based research. 5 refs., 5 figs

  19. The neutron porosity tool

    International Nuclear Information System (INIS)

    Oelgaard, P.L.

    1988-01-01

    The report contains a review of available information on neutron porosity tools with the emphasis on dual thermal-neutron-detector porosity tools and epithermal-neutron-detector porosity tools. The general principle of such tools is discussed and theoretical models are very briefly reviewed. Available data on tool designs are summarized with special regard to the source-detector distance. Tool operational data, porosity determination and correction of measurements are briefly discussed. (author) 15 refs

  20. Individual neutron dosimetry

    International Nuclear Information System (INIS)

    Mauricio, C.L.P.

    1987-01-01

    The most important concepts and development in individual neutron dosimetry are presented, especially the dosimetric properties of the albedo technique. The main problem in albedo dosimetry is to calibrate the dosemeter in the environs of each neutron source. Some of the most used calibration techniques are discussed. The IRD albedo dosemeter used in the routine neutron individual monitoring is described in detail. Its dosimetric properties and calibration methods are discussed. (Author) [pt

  1. The advanced neutron source

    International Nuclear Information System (INIS)

    Raman, S.; Hayter, J.B.

    1990-01-01

    The Advanced Neutron Source (ANS) is a new user experimental facility planned to be operational at Oak Ridge in the late 1990's. The centerpiece of the ANS will be a steady-state research reactor of unprecedented thermal neutron flux (φ th ∼ 8 x 10 19 m -2 ·s -1 ) accompanied by extensive and comprehensive equipment and facilities for neutron-based research

  2. ATR neutron spectral characterization

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, J.W.; Anderl, R.A.

    1995-11-01

    The Advanced Test Reactor (ATR) at INEL provides intense neutron fields for irradiation-effects testing of reactor material samples, for production of radionuclides used in industrial and medical applications, and for scientific research. Characterization of the neutron environments in the irradiation locations of the ATR has been done by means of neutronics calculations and by means of neutron dosimetry based on the use of neutron activation monitors that are placed in the various irradiation locations. The primary purpose of this report is to present the results of an extensive characterization of several ATR irradiation locations based on neutron dosimetry measurements and on least-squares-adjustment analyses that utilize both neutron dosimetry measurements and neutronics calculations. This report builds upon the previous publications, especially the reference 4 paper. Section 2 provides a brief description of the ATR and it tabulates neutron spectral information for typical irradiation locations, as derived from the more historical neutron dosimetry measurements. Relevant details that pertain to the multigroup neutron spectral characterization are covered in section 3. This discussion includes a presentation on the dosimeter irradiation and analyses and a development of the least-squares adjustment methodology, along with a summary of the results of these analyses. Spectrum-averaged cross sections for neutron monitoring and for displacement-damage prediction in Fe, Cr, and Ni are given in section 4. In addition, section4 includes estimates of damage generation rates for these materials in selected ATR irradiation locations. In section 5, the authors present a brief discussion of the most significant conclusions of this work and comment on its relevance to the present ATR core configuration. Finally, detailed numerical and graphical results for the spectrum-characterization analyses in each irradiation location are provided in the Appendix.

  3. Statistical theory for calculating energy spectra of β-delayed neutrons

    International Nuclear Information System (INIS)

    Kawano, Toshihiko; Moeller, Peter; Wilson, William B.

    2008-01-01

    Theoretical β-delayed neutron spectra are calculated based on the Quasi-particle Random Phase Approximation (QRPA) and the Hauser-Feshbach statistical model. Neutron emissions from an excited daughter nucleus after β-decay to the granddaughter residual are more accurately calculated than previous evaluations, including all the microscopic nuclear structure information, such as a Gamow-Teller strength distribution and discrete states in the granddaughter. The calculated delayed-neutron spectra reasonably agree with those evaluations in the ENDF decay library, which are based on experimental data. The model was adopted to generate the delayed-neutron spectra for all 271 precursors. (authors)

  4. Neutrons for probing matter

    International Nuclear Information System (INIS)

    Torres, F. Ed.; Mazzucchetti, D.

    2008-01-01

    The authors tell the story of the French Orphee reactor located in Saclay from the decision to build it in the seventies, to its commissioning in 1980, to its upgrading in the nineties and to its today's operating life. As early as its feasibility studies Orphee has been designed as a dual-purpose reactor: scientific research for instance in crystallography and magnetism, and industrial uses like neutron radiography, silicon doping or radionuclide production. This book is divided into 4 parts: 1) the neutron: an explorer of the matter, 2) the Orphee reactor: a neutron source, 3) the adventurers of the matter: Leon Brillouin laboratory's staff, and 4) the perspectives for neutrons

  5. Spallation neutrons pulsed sources

    International Nuclear Information System (INIS)

    Carpenter, J.

    1996-01-01

    This article describes the range of scientific applications which can use these pulsed neutrons sources: Studies on super fluids, measures to verify the crawling model for the polymers diffusion; these sources are also useful to study the neutron disintegration, the ultra cold neutrons. In certain applications which were not accessible by neutrons diffusion, for example, radiations damages, radionuclides production and activation analysis, the spallation sources find their use and their improvement will bring new possibilities. Among others contributions, one must notice the place at disposal of pulsed muons sources and neutrinos sources. (N.C.). 3 figs

  6. Microcomputerized neutron moisture gauge

    International Nuclear Information System (INIS)

    Liu Shengkang; Mei Yu

    1987-01-01

    A microcomputerized neutron moisture gauge is introduced. This gauge consists of a neutron moisture sensor and instruments. It is developed from the neutron moisture gauge for concrete mixer. A TECH-81 single card microcomputer is used for count, computation and display. It has the function of computing compensated quantity of sand. It can acquire the data from several neutron sensors by the multichanneling sampling, therefore it can measure moisture values of sand in several hoppers simultaneously. The precision of the static state calibration curve is 0.24% wt. The error limits of the dynamic state check is < 0.50% wt

  7. Neutrons from Antiproton Irradiation

    DEFF Research Database (Denmark)

    Bassler, Niels; Holzscheiter, Michael; Petersen, Jørgen B.B.

    the neutron spectrum. Additionally, we used a cylindrical polystyrene loaded with several pairs of thermoluminescent detectors containing Lithium-6 and Lithium-7, which effectively detects thermalized neutrons. The obtained results are compared with FLUKA imulations. Results: The results obtained...... spectrum is very low, and does not pose a problem for radiation therapy. However, the contribution from fast neutrons is much more significant. The dose equivalent contribution from neutrons originate from the patient alone and reaches levels which are found in passive moderated proton therapy. The exact...

  8. Introduction to neutron stars

    Energy Technology Data Exchange (ETDEWEB)

    Lattimer, James M. [Dept. of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794-3800 (United States)

    2015-02-24

    Neutron stars contain the densest form of matter in the present universe. General relativity and causality set important constraints to their compactness. In addition, analytic GR solutions are useful in understanding the relationships that exist among the maximum mass, radii, moments of inertia, and tidal Love numbers of neutron stars, all of which are accessible to observation. Some of these relations are independent of the underlying dense matter equation of state, while others are very sensitive to the equation of state. Recent observations of neutron stars from pulsar timing, quiescent X-ray emission from binaries, and Type I X-ray bursts can set important constraints on the structure of neutron stars and the underlying equation of state. In addition, measurements of thermal radiation from neutron stars has uncovered the possible existence of neutron and proton superfluidity/superconductivity in the core of a neutron star, as well as offering powerful evidence that typical neutron stars have significant crusts. These observations impose constraints on the existence of strange quark matter stars, and limit the possibility that abundant deconfined quark matter or hyperons exist in the cores of neutron stars.

  9. Neutron detection technique

    International Nuclear Information System (INIS)

    Oblath, N.S.; Poon, A.W.P.

    2000-01-01

    The Sudbury Neutrino Observatory (SNO) has the ability to measure the total flux of all active flavors of neutrinos using the neutral current reaction, whose signature is a neutron. By comparing the rates of the neutral current reaction to the charged current reaction, which only detects electron neutrinos, one can test the neutrino oscillation hypothesis independent of solar models. It is necessary to understand the neutron detection efficiency of the detector to make use of the neutral current reaction. This report demonstrates a coincidence technique to identify neutrons emitted from the 252 Cf neutron calibration source. The source releases on average four neutrons when a 252 Cf nucleus spontaneously fissions. Each neutron is detected as a separate event when the neutron is captured by a deuteron, releasing a gamma ray of approximately 6.25 MeV. This gamma ray is in turn detected by the photomultiplier tube (PMT) array. By investigating the time and spatial separation between neutron-like events, it is possible to obtain a pure sample of neutrons for calibration study. Preliminary results of the technique applied to two calibration runs are presented

  10. Neutron scattering. Experiment manuals

    International Nuclear Information System (INIS)

    Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner

    2014-01-01

    The following topics are dealt with: The thermal triple-axis spectrometer PUMA, the high-resolution powder diffractometer SPODI, the hot-single-crystal diffractometer HEiDi, the three-axis spectrometer PANDA, the backscattering spectrometer SPHERES, the DNS neutron-polarization analysis, the neutron spin-echo spectrometer J-NSE, small-angle neutron scattering at KWS-1 and KWS-2, a very-small-angle neutron scattering diffractometer with focusing mirror, the reflectometer TREFF, the time-of-flight spectrometer TOFTOF. (HSI)

  11. Neutrons in biology

    International Nuclear Information System (INIS)

    Funahashi, Satoru; Niimura, Nobuo.

    1993-01-01

    The start of JRR-3M in 1990 was a great epoch to the neutron scattering research in Japan. Abundant neutron beam generated by the JRR-3M made it possible to widen the research field of neutron scattering in Japan. In the early days of neutron scattering, biological materials were too difficult object to be studied by neutrons not only because of their complexity but also because of the strong incoherent scattering by hydrogen. However, the remarkable development of the recent neutron scattering and its related sciences, as well as the availability of higher flux, has made the biological materials one of the most attractive subjects to be studied by neutrons. In early September 1992, an intensive workshop titled 'Neutrons in Biology' was held in Hitachi City by making use of the opportunity of the 4th International Conference on Biophysics and Synchrotron Radiation (BSR92) held in Tsukuba. The workshop was organized by volunteers who are eager to develop the researches in this field in Japan. Numbers of outstanding neutron scattering biologists from U.S., Europe and Asian countries met together and enthusiastic discussions were held all day long. The editors believe that the presentations at the workshop were so invaluable that it is absolutely adequate to put them on record as an issue of JAERI-M and to make them available for scientists to refer to in order to further promote the research in the future. (author)

  12. Polycapillary neutron lenses

    International Nuclear Information System (INIS)

    Mildner, D.F.R.

    1997-01-01

    The principle of multiple mirror reflection from smooth surfaces at small grazing angles enables the transport and guiding of high intensity slow neutron beams to locations of low background for neutron scattering and absorption experiments and to provide facilities for multiple instruments. Curved guides have been widely used at cold neutron facilities to remove the unwanted radiation (fast neutrons and gamma rays) from the beam without the use of filters. A typical guide has transverse dimensions of 50 mm and, with a radius of curvature of 1 km, transmits wavelengths longer than 5 A. Much tighter curves requires narrower transverse dimensions, otherwise there is little transmission. Typical neutron benders have a number of slots with transverse dimensions of ∼5 mm. Based on the same principle but using a different technology, recent developments in glass polycapillary fibers have produced miniature versions of neutron guides. Fibers with many thousands of channels having sizes of ∼ 10 μm enable beams of long wavelength neutrons (λ > 4 A) to be transmitted efficiently in a radius of curvature as small as a fraction of 1 m. A large collection of these miniature versions of neutron guides can be used to bend the neutron trajectories such that the incident beam can be focused. (author)

  13. Neutron structural biology

    International Nuclear Information System (INIS)

    Niimura, Nobuo

    1999-01-01

    Neutron structural biology will be one of the most important fields in the life sciences which will interest human beings in the 21st century because neutrons can provide not only the position of hydrogen atoms in biological macromolecules but also the dynamic molecular motion of hydrogen atoms and water molecules. However, there are only a few examples experimentally determined at present because of the lack of neutron source intensity. Next generation neutron source scheduled in JAERI (Performance of which is 100 times better than that of JRR-3M) opens the life science of the 21st century. (author)

  14. Complex scaling and residual flavour symmetry in the neutrino mass ...

    Indian Academy of Sciences (India)

    Probir Roy

    2017-10-09

    Oct 9, 2017 ... Leptonic Dirac CP violation must be maximal while atmospheric neutrino mixing need not be exactly maximal. Each of the two Majorana phases, to be probed by the search for 0νββ decay, has to be zero or π and a normal neutrino mass hierarchy is allowed. Keywords. Neutrinos; residual flavour symmetry; ...

  15. Evaluation of residue-residue contact predictions in CASP9

    KAUST Repository

    Monastyrskyy, Bohdan; Fidelis, Krzysztof; Tramontano, Anna; Kryshtafovych, Andriy

    2011-01-01

    This work presents the results of the assessment of the intramolecular residue-residue contact predictions submitted to CASP9. The methodology for the assessment does not differ from that used in previous CASPs, with two basic evaluation measures

  16. JRR-3 neutron radiography facility

    International Nuclear Information System (INIS)

    Matsubayashi, M.; Tsuruno, A.

    1992-01-01

    JRR-3 neutron radiography facility consists of thermal neutron radiography facility (TNRF) and cold neutron radiography facility (CNRF). TNRF is installed in JRR-3 reactor building. CNRF is installed in the experimental beam hall adjacent to the reactor building. (author)

  17. Thermoluminescence albedo-neutron dosimetry

    International Nuclear Information System (INIS)

    Strand, T.; Storruste, A.

    1986-10-01

    The report discusses neutron detection with respect to dosimetry and compares different thermoluminescent dosimetry materials for neutron dosimetry. Construction and calibration of a thermoluminescence albedo neutron dosemeter, developed by the authors, is described

  18. Beam test of the 2D position sensitive neutron detector

    International Nuclear Information System (INIS)

    Tian Lichao; Chen Yuanbo; Sun Zhijia; Tang Bin; Zhou Jianrong; Qi Huirong; Liu Rongguang; Zhang Jian; Yang Guian; Xu Hong

    2014-01-01

    China Spallation Neutron Source (CSNS), one of the Major scientific apparatuses of the national Eleventh Five-Year Plane, is under construction and three spectrumeters will be constructed in the first phase of the project. A 2D position sensitive neutron detector has been constructed for the Multifunctional Reflect spectrumeter (MR) in Institute of High Energy Physics (IHEP). The basic operation principle of the detector and the test on the residual stress diffractometer of Chinese Advanced Research Reactor (CARR) in China Institute of Atomic Energy (CIAE) is introduced in this paper. The results show that it has a good position resolution of l.18 mm (FWHM) for the neutrons of l.37 A and 2D imaging ability, which is consistent with the theory. It can satisfy the requirements of MR and lays the foundation for the construction of larger neutron detectors. (authors)

  19. Atmospheric chemistry and climate

    OpenAIRE

    Satheesh, SK

    2012-01-01

    Atmospheric chemistry is a branch of atmospheric science where major focus is the composition of the Earth's atmosphere. Knowledge of atmospheric composition is essential due to its interaction with (solar and terrestrial) radiation and interactions of atmospheric species (gaseous and particulate matter) with living organisms. Since atmospheric chemistry covers a vast range of topics, in this article the focus is on the chemistry of atmospheric aerosols with special emphasis on the Indian reg...

  20. Sharing Residual Liability

    DEFF Research Database (Denmark)

    Carbonara, Emanuela; Guerra, Alice; Parisi, Francesco

    2016-01-01

    Economic models of tort law evaluate the efficiency of liability rules in terms of care and activity levels. A liability regime is optimal when it creates incentives to maximize the value of risky activities net of accident and precaution costs. The allocation of primary and residual liability...... for policy makers and courts in awarding damages in a large number of real-world accident cases....

  1. Fast neutron dosimetry. Progress report, July 1, 1979-June 30, 1980

    Energy Technology Data Exchange (ETDEWEB)

    Attix, F.H.

    1980-01-01

    Progress is reported in: the development and testing of new gas mixtures more suitable for fast neutron dosimetry using the common A150-type Tissue-equivalent plastic ion chambers; comparison of photon doses determined with a graphite-walled proportional counter and with paired dosimeters irradiated by 14.8-MeV neutrons; a detector for the direct measurement of LET distributions from irradiation with fast neutrons; LET distributions from fast neutron irradiation of TE-plastic and graphite measured in a cylindrically symmetric geometry; progress in development of a tandem fast neutron and /sup 60/Co gamma ray source irradiation facility; an approach to the correlation of cellular response with lineal energy; calculated and measured HTO atmospheric dispersion rates within meters of a release site; application of cavity theory to fast neutrons; and fast neutron dosimetry by thermally stimulated currents in Al/sub 2/O/sub 3/. (GHT)

  2. Cosmic-ray-induced ship-effect neutron measurements and implications for cargo scanning at borders

    Energy Technology Data Exchange (ETDEWEB)

    Kouzes, Richard T. [Pacific Northwest National Laboratory, MS K7-36, P.O. Box 999, Richland, WA 99352 (United States)], E-mail: richard.kouzes@pnl.gov; Ely, James H.; Seifert, Allen; Siciliano, Edward R.; Weier, Dennis R.; Windsor, Lindsay K.; Woodring, Mitchell L. [Pacific Northwest National Laboratory, MS K7-36, P.O. Box 999, Richland, WA 99352 (United States); Borgardt, James; Buckley, Elise; Flumerfelt, Eric; Oliveri, Anna; Salvitti, Matt [Juniata College Physics Department, 1700 Moore St., Huntingdon, PA 16652 (United States)

    2008-03-11

    Neutron measurements are used as part of the interdiction process for illicit nuclear materials at border crossings. Even though the natural neutron background is small, its variation can impact the sensitivity of detection systems. The natural background of neutrons that is observed in monitoring instruments arises almost entirely from cosmic-ray-induced cascades in the atmosphere and the surrounding environment. One significant source of variation in the observed neutron background is produced by the 'ship effect' in large quantities of cargo that transit past detection instruments. This paper reports on results from measurements with typical monitoring equipment of ship effect neutrons in various materials. One new result is the 'neutron shadow shielding' effect seen with some low neutron density materials.

  3. Fast neutron dosimetry. Progress report, July 1, 1979-June 30, 1980

    International Nuclear Information System (INIS)

    Attix, F.H.

    1980-01-01

    Progress is reported in: the development and testing of new gas mixtures more suitable for fast neutron dosimetry using the common A150-type Tissue-equivalent plastic ion chambers; comparison of photon doses determined with a graphite-walled proportional counter and with paired dosimeters irradiated by 14.8-MeV neutrons; a detector for the direct measurement of LET distributions from irradiation with fast neutrons; LET distributions from fast neutron irradiation of TE-plastic and graphite measured in a cylindrically symmetric geometry; progress in development of a tandem fast neutron and 60 Co gamma ray source irradiation facility; an approach to the correlation of cellular response with lineal energy; calculated and measured HTO atmospheric dispersion rates within meters of a release site; application of cavity theory to fast neutrons; and fast neutron dosimetry by thermally stimulated currents in Al 2 O 3

  4. Wide range neutron detection system

    International Nuclear Information System (INIS)

    Todt, W.H. Sr.

    1978-01-01

    A neutron detection system for reactor control is described which is operable over a wide range of neutron flux levels. The system includes a fission type ionization chamber neutron detector, means for gamma and alpha signal compensation, and means for operating the neutron detector in the pulse counting mode for low neutron flux levels, and in the direct current mode for high neutron flux levels

  5. MADNIX a code to calculate prompt fission neutron spectra and average prompt neutron multiplicities

    International Nuclear Information System (INIS)

    Merchant, A.C.

    1986-03-01

    A code has been written and tested on the CDC Cyber-170 to calculate the prompt fission neutron spectrum, N(E), as a function of both the fissioning nucleus and its excitation energy. In this note a brief description of the underlying physical principles involved and a detailed explanation of the required input data (together with a sample output for the fission of 235 U induced by 14 MeV neutrons) are presented. Weisskopf's standard nuclear evaporation theory provides the basis for the calculation. Two important refinements are that the distribution of fission-fragment residual nuclear temperature and the cooling of the fragments as neutrons are emitted approximately taken into account, and also the energy dependence of the cross section for the inverse process of compound nucleus formation is included. This approach is then used to calculate the average number of prompt neutrons emitted per fission, v-bar p . At high excitation energies, where fission is still possible after neutron emission, the consequences of the competition between first, second and third chance fission on N(E) and v-bar p are calculated. Excellent agreement with all the examples given in the original work of Madland and Nix is obtained. (author) [pt

  6. Effect of different lay-ups on the microstructure, mechanical properties and neutron transmission of neutron shielding fibre metal laminates

    International Nuclear Information System (INIS)

    Fu, Xuelong; Tang, Xiaobin; Hu, Yubing; Li, Huaguan; Tao, Jie

    2016-01-01

    A novel neutron shielding fibre metal laminates (NSFMLs) with different lay-ups, composed of stacking layers of AA6061 plates, neutron shielding composite and carbon fibre reinforced polyimide (CFRP), were fabricated using hot molding process in atmospheric environments. The microstructure, mechanical properties and neutron transmission of the NSFMLs were evaluated, respectively. The results indicated that the NSFMLs possessed good mechanical properties owing to the good interfacial adhesion of the components. Tensile strength and elastic modulus of the NSFMLs increased with the numbers of lay-ups, while the elongation to fracture exhibited obvious declining tendency. Flexural strength and modulus of the NSFMLs were improved obviously with the increasing of stacking layers. Neutron transmission of the NSFMLs decreased obviously with increasing the number of lay-ups, owing to the increase of "1"0B areal density. Besides, the effect of carbon fibres on the neutron shielding performance of the NSFMLs was also taken into consideration. - Highlights: • A novel neutron shielding fibre metal laminates (NSFMLs) with different lay-ups was successfully fabricated using hot molding process. • Mechanical properties of the NSFMLs were performed in accordance with relative standards. • Neutron transmission of the NSFMLs was conducted according to the testing results. • The effect of carbon fibres on the neutron transmission of the NSFMLs was also investigated.

  7. Effect of different lay-ups on the microstructure, mechanical properties and neutron transmission of neutron shielding fibre metal laminates

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Xuelong [College of Material Science & Technology, Nanjing University of Aeronautics & Astronautics, Nanjing, 211100 (China); Department of Mechanical and Electronic Engineering, Jiangsu Polytechnic of Finance & Economics, Huai' an, 223003 (China); Tang, Xiaobin; Hu, Yubing; Li, Huaguan [College of Material Science & Technology, Nanjing University of Aeronautics & Astronautics, Nanjing, 211100 (China); Tao, Jie, E-mail: taojie@nuaa.edu.cn [College of Material Science & Technology, Nanjing University of Aeronautics & Astronautics, Nanjing, 211100 (China)

    2016-07-15

    A novel neutron shielding fibre metal laminates (NSFMLs) with different lay-ups, composed of stacking layers of AA6061 plates, neutron shielding composite and carbon fibre reinforced polyimide (CFRP), were fabricated using hot molding process in atmospheric environments. The microstructure, mechanical properties and neutron transmission of the NSFMLs were evaluated, respectively. The results indicated that the NSFMLs possessed good mechanical properties owing to the good interfacial adhesion of the components. Tensile strength and elastic modulus of the NSFMLs increased with the numbers of lay-ups, while the elongation to fracture exhibited obvious declining tendency. Flexural strength and modulus of the NSFMLs were improved obviously with the increasing of stacking layers. Neutron transmission of the NSFMLs decreased obviously with increasing the number of lay-ups, owing to the increase of {sup 10}B areal density. Besides, the effect of carbon fibres on the neutron shielding performance of the NSFMLs was also taken into consideration. - Highlights: • A novel neutron shielding fibre metal laminates (NSFMLs) with different lay-ups was successfully fabricated using hot molding process. • Mechanical properties of the NSFMLs were performed in accordance with relative standards. • Neutron transmission of the NSFMLs was conducted according to the testing results. • The effect of carbon fibres on the neutron transmission of the NSFMLs was also investigated.

  8. J-PARC and the prospective neutron sciences

    International Nuclear Information System (INIS)

    Masatoshi Arai

    2009-01-01

    Full text: J-PARC is an interdisciplinary facility with high power proton accelerator complex containing particle physics, nuclear physics, muon science and neutron science facilities. After 8 years construction, she is almost ready to open for users. Materials-Life Science Facility (MLF) of J-PARC is composed from very intensive pulsed neutron and muon facilities at 1 MW of the accelerated proton power. The neutron peak flux will be as high as several hundred times of existing high flux reactors. Therefore, it is highly expected that new sciences will be explored by J-PARC, MLF. The first neutrons was already produced in the last May. The MLF facility has 23 neutron beam ports. About 12 instruments are under commissioning or construction. Out of four instruments are already opened for users since December, 2008.. In the commissioning High Resolution Powder Diffractometer showed the world highest resolution d/d=0.04% as was designed. Other instruments, high intensity powder diffractometer, protein crystal diffractometer, residual stress analysis diffractometer, high intensity chopper spectrometer, confirmed expected intensity and spectrum from neutron beam line. By the end of March, a cold neutron chopper spectrometer will also come on line. Those instruments are taking advantages with optical devices for neutron transport to realize very high flux at sample position. By taking high performances of neutron moderators of MLF, the instruments will realize the world class resolution and high intensity. Ranging from Bio-science, material science, engineering, industrial use of neutrons to fundamental physics, we are exciting to see cutting-edge sciences with great anticipation to be produced from J-PARC, MLF. (author)

  9. Neutron monitoring for radiological protection

    International Nuclear Information System (INIS)

    Gibson, J.A.B.

    1985-01-01

    Neutron monitoring is a subject of increasing general interest and considerable attention is being paid to the development of improved techniques and methods for neutron monitoring. The Agency, therefore, considered it important to prepare a guide on the subject of neutron monitoring for radiation protection purposes. The present Manual is intended for those persons or authorities in Member States, particularly developing countries, who are responsible for the organization of neutron monitoring programmes and practical neutron monitoring. This Manual consequently, deals with topics such as neutron dosimetry, sources of neutrons and neutron detection as well as field instruments and operational systems used in this context

  10. Residual stresses and stress corrosion cracking in pipe fittings

    International Nuclear Information System (INIS)

    Parrington, R.J.; Scott, J.J.; Torres, F.

    1994-06-01

    Residual stresses can play a key role in the SCC performance of susceptible materials in PWR primary water applications. Residual stresses are stresses stored within the metal that develop during deformation and persist in the absence of external forces or temperature gradients. Sources of residual stresses in pipe fittings include fabrication processes, installation and welding. There are a number of methods to characterize the magnitude and orientation of residual stresses. These include numerical analysis, chemical cracking tests, and measurement (e.g., X-ray diffraction, neutron diffraction, strain gage/hole drilling, strain gage/trepanning, strain gage/section and layer removal, and acoustics). This paper presents 400 C steam SCC test results demonstrating that residual stresses in as-fabricated Alloy 600 pipe fittings are sufficient to induce SCC. Residual stresses present in as-fabricated pipe fittings are characterized by chemical cracking tests (stainless steel fittings tested in boiling magnesium chloride solution) and by the sectioning and layer removal (SLR) technique

  11. Radionuclides in Bayer process residues: previous analysis for radiological protection

    International Nuclear Information System (INIS)

    Cuccia, Valeria; Rocha, Zildete; Oliveira, Arno H. de

    2011-01-01

    Natural occurring radionuclides are present in many natural resources. Human activities may enhance concentrations of radionuclides and/or enhance potential of exposure to naturally occurring radioactive material (NORM). The industrial residues containing radionuclides have been receiving a considerable global attention, because of the large amounts of NORM containing wastes and the potential long term risks of long-lived radionuclides. Included in this global concern, this work focuses on the characterization of radioactivity in the main residues of Bayer process for alumina production: red mud and sand samples. Usually, the residues of Bayer process are named red mud, in their totality. However, in the industry where the samples were collected, there is an additional residues separation: sand and red mud. The analytical techniques used were gamma spectrometry (HPGe detector) and neutron activation analysis. The concentrations of radionuclides are higher in the red mud than in the sand. These solid residues present activities concentrations enhanced, when compared to bauxite. Further uses for the residues as building material must be more evaluated from the radiological point of view, due to its potential of radiological exposure enhancement, specially caused by radon emission. (author)

  12. Residual radiation in Hiroshima and Nagasaki

    Energy Technology Data Exchange (ETDEWEB)

    Arakawa, E T

    1962-02-01

    These results show that the fission product fallout and neutron-induced radioactive isotopes can be separated very conveniently by locations in the city, i.e., the fallout occurred in the Koi-Takasu area of Hiroshima and the Nishiyama area of Nagasaki with negligible fallout in the hypocenter area. The activity in the hypocenter areas of both cities can be accounted for as due principally to neutron induced radioactive isotopes. The maximum exposure from fallout in Hiroshima is considered to have been a few r and in Nagasaki approximately 30 r. From one hour to infinite time after the detonations, the maximum possible neutron induced radiation exposure dose at the hypocenter in Hiroshima is estimated to be in the range from 183 r to 24 r, depending upon the method of calculation. Method III, which yileds 24 r appears to be subject to the least number of uncertainties and thus is the most reliable figure. The excellent agreement between these calculations and the measured activities also further supports the soundness of Method III. This method gives 4 r as the infinity dose at the hypocenter in Nagasaki. These values are considered to be of such loss magnitude as to be of negligible consequence. It should also be emphasized that even for the calculation which yields a maximum dose of 183 r, the probability of an individual being exposed to this dose is very small. These facts suggest that after the detonations in Hiroshima and Nagasaki radiation levels were such that very few individuals, if any, received significant amounts of residual radiation from external sources. 17 references, 4 figures, 3 tables.

  13. Neutron spectroscopy, nuclear structure, related topics. Abstracts

    International Nuclear Information System (INIS)

    Sukhovoj, A.M.

    1996-01-01

    Neutron spectroscopy, nuclear structure and related topics are considered. P, T-breaking, neutron beta decay, neutron radiative capture and neutron polarizability are discussed. Reaction with fast neutrons, methodical aspect low-energy fission are considered too

  14. Liquid oil and residual characteristics of printed circuit board recycle by pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Kuo-Hsiung [Department of Environmental Engineering and Science, Fooyin University, Kaohsiung, Taiwan (China); Chiang, Hung-Lung, E-mail: hlchiang@mail.cmu.edu.tw [Department of Health Risk Management, China Medical University, Taichung, Taiwan (China)

    2014-04-01

    Highlights: • Pyrolysis is a technology for recycling of the non-metal fraction of PCBs. • Liquid product constituents were analyzed for PCB pyrolysis. • Water-soluble ionic species were determined for PCB pyrolysis exhaust. - Abstract: Non-metal fractions of waste printed circuit boards (PCBs) were thermally treated (200–500 °C) under nitrogen atmosphere. Carbon, hydrogen, and nitrogen were determined by elemental analyzer, bromine by instrumental neutron activation analysis (INAA), phosphorus by energy dispersive X-ray spectrometer (EDX), and 29 trace elements by inductively coupled plasma atomic emission spectrometer (ICP-AES) and mass spectrometry (ICP-MS) for raw material and pyrolysis residues. Organic compositions of liquid oil were identified by GC (gas chromatography)–MS, trace element composition by ICP system, and 12 water-soluble ions by IC (ionic chromatography). Elemental content of carbon was >450 mg/g, oxygen 300 mg/g, bromine and hydrogen 60 mg/g, nitrogen 30 mg/g, and phosphorus 28 mg/g. Sulfur was trace in PCBs. Copper content was 25–28 mg/g, iron 1.3–1.7 mg/g, tin 0.8–1.0 mg/g and magnesium 0.4–1.0 mg/g; those were the main metals in the raw materials and pyrolytic residues. In the liquid products, carbon content was 68–73%, hydrogen was 10–14%, nitrogen was 4–5%, and sulfur was less than 0.05% at pyrolysis temperatures from 300 to 500 °C. Phenol, 3-bromophenol, 2-methylphenol and 4-propan-2-ylphenol were major species in liquid products, accounting for >50% of analyzed organic species. Bromides, ammonium and phosphate were the main species in water sorption samples for PCB pyrolysis exhaust.

  15. Laser neutron generator

    International Nuclear Information System (INIS)

    Anan'in, O.B.; Bespalov, D.F.; Bykovskii, Yu.A.; Kozyrev, Yu.P.; Mints, A.Z.; Riabov, E.V.; Tsybin, A.S.; Cherkasov, Yu.; Shikanov, A.E.

    1986-01-01

    Information is presented concerning devices for producing intense neutrons flows, and may be utilized in nuclear geophysics for carrying out pulsed neutron logging of wells, in studies of the critical characteristics of nuclear reactors, for activation analysis, radiation therapy, defectoscopy, and so on

  16. Muons, neutrons and superconductivity

    International Nuclear Information System (INIS)

    Aeppli, G.; Risoe National Lab., Roskilde

    1988-01-01

    The principles of the neutron scattering and muon spin relaxation (μSR) techniques and their applications to studies of superconductors are described briefly. μSR and neutron scattering work on magnetic correlations in superconductors and materials directly related to superconductors are reviewed. (orig.)

  17. Neutron resonance spectroscopy

    International Nuclear Information System (INIS)

    Gunsing, F.

    2005-06-01

    The present document has been written in order to obtain the diploma 'Habilitation a Diriger des Recherches'. Since this diploma is indispensable to supervise thesis students, I had the intention to write a document that can be useful for someone starting in the field of neutron resonance spectroscopy. Although the here described topics are already described elsewhere, and often in more detail, it seemed useful to have most of the relevant information in a single document. A general introduction places the topic of neutron-nucleus interaction in a nuclear physics context. The large variations of several orders of magnitude in neutron-induced reaction cross sections are explained in terms of nuclear level excitations. The random character of the resonances make nuclear model calculation predictions impossible. Then several fields in physics where neutron-induced reactions are important and to which I have contributed in some way or another, are mentioned in a first synthetic chapter. They concern topics like parity nonconservation in certain neutron resonances, stellar nucleosynthesis by neutron capture, and data for nuclear energy applications. The latter item is especially important for the transmutation of nuclear waste and for alternative fuel cycles. Nuclear data libraries are also briefly mentioned. A second chapter details the R-matrix theory. This formalism is the foundation of the description of the neutron-nucleus interaction and is present in all fields of neutron resonance spectroscopy. (author)

  18. Neutron resonance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Gunsing, F

    2005-06-15

    The present document has been written in order to obtain the diploma 'Habilitation a Diriger des Recherches'. Since this diploma is indispensable to supervise thesis students, I had the intention to write a document that can be useful for someone starting in the field of neutron resonance spectroscopy. Although the here described topics are already described elsewhere, and often in more detail, it seemed useful to have most of the relevant information in a single document. A general introduction places the topic of neutron-nucleus interaction in a nuclear physics context. The large variations of several orders of magnitude in neutron-induced reaction cross sections are explained in terms of nuclear level excitations. The random character of the resonances make nuclear model calculation predictions impossible. Then several fields in physics where neutron-induced reactions are important and to which I have contributed in some way or another, are mentioned in a first synthetic chapter. They concern topics like parity nonconservation in certain neutron resonances, stellar nucleosynthesis by neutron capture, and data for nuclear energy applications. The latter item is especially important for the transmutation of nuclear waste and for alternative fuel cycles. Nuclear data libraries are also briefly mentioned. A second chapter details the R-matrix theory. This formalism is the foundation of the description of the neutron-nucleus interaction and is present in all fields of neutron resonance spectroscopy. (author)

  19. Lunar neutron source function

    International Nuclear Information System (INIS)

    Kornblum, J.J.

    1974-01-01

    The search for a quantitative neutron source function for the lunar surface region is justified because it contributes to our understanding of the history of the lunar surface and of nuclear process occurring on the moon since its formation. A knowledge of the neutron source function and neutron flux distribution is important for the interpretation of many experimental measurements. This dissertation uses the available pertinent experimental measurements together with theoretical calculations to obtain an estimate of the lunar neutron source function below 15 MeV. Based upon reasonable assumptions a lunar neutron source function having adjustable parameters is assumed for neutrons below 15 MeV. The lunar neutron source function is composed of several components resulting from the action of cosmic rays with lunar material. A comparison with previous neutron calculations is made and significant differences are discussed. Application of the results to the problem of lunar soil histories is examined using the statistical model for soil development proposed by Fireman. The conclusion is drawn that the moon is losing mass

  20. Neutron Multiplicity Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Frame, Katherine Chiyoko [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-06-28

    Neutron multiplicity measurements are widely used for nondestructive assay (NDA) of special nuclear material (SNM). When combined with isotopic composition information, neutron multiplicity analysis can be used to estimate the spontaneous fission rate and leakage multiplication of SNM. When combined with isotopic information, the total mass of fissile material can also be determined. This presentation provides an overview of this technique.

  1. Applications of polarized neutrons

    International Nuclear Information System (INIS)

    Mezei, F.

    1993-01-01

    The additional spin degree of freedom of the neutron can be made use of in neutron scattering work in two fundamental ways: (a) directly for the identification of magnetic scattering effects and (b) indirectly as a spectroscopic tool for modulating and analysing beams. Although strong magnetic scattering contributions can often be studied by unpolarized neutrons, a fully unambiguous separation of nuclear and magnetic phenomena can only be achieved by the additional information provided by polarized neutrons, especially if one of the two kinds of contributions is weak compared to the other. In the most general case a sample with both magnetic and nuclear features can be characterized by as many as 16 independent dynamic correlation functions instead of the single well known S(q, ω) for non-magnetic nuclear scattering only. Polarization analysis in principle allows one to determine all these 16 functions. The indirect applications of polarized neutrons are also steadily gaining importance. The most widely used method of this kind, the application of Larmor precessions for high resolution energy analysis in Neutron Spin Echo spectroscopy opened up a whole new domain in inelastic neutron scattering which was not accessible to any other spectroscopic method with or without neutrons before. (author)

  2. Symposium on neutron scattering

    International Nuclear Information System (INIS)

    Lehmann, M.S.; Saenger, W.; Hildebrandt, G.; Dachs, H.

    1984-01-01

    Extended abstracts of the named symposium are presented. The first part of this report contains the abstracts of the lectures, the second those of the posters. Topics discussed on the symposium include neutron diffraction and neutron scattering studies in magnetism, solid state chemistry and physics, materials research. Some papers discussing instruments and methods are included too. (GSCH)

  3. filled neutron detectors

    Indian Academy of Sciences (India)

    Boron trifluoride (BF3) proportional counters are used as detectors for thermal neutrons. They are characterized by high neutron sensitivity and good gamma discriminating properties. Most practical BF3 counters are filled with pure boron trifluoride gas enriched up to 96% 10B. But BF3 is not an ideal proportional counter ...

  4. Mathematical methods in neutronics

    International Nuclear Information System (INIS)

    Planchard, J.

    1995-01-01

    This book presents the mathematical theory of nuclear reactors. It applies to engineers in neutronics and applied mathematicians. After a recall of the elementary notions of neutronics and of diffusion-type partial derivative equations, the theory of reactors criticality calculation is described. (J.S.)

  5. Multidisc neutron velocity selector

    International Nuclear Information System (INIS)

    Rosta, L.; Zsigmond, Gy.; Farago, B.; Mezei, F.; Ban, K.; Perendi, J.

    1987-12-01

    The prototype of a velocity selector for neutron monochromatization in the 4-20 A wavelength range is presented. The theoretical background of the multidisc rotor system is given together with a description of the mechanical construction and electronic driving system. The first tests and neutron measurements prove easy handling and excellent parameters. (author) 6 refs.; 7 figs.; 2 tabs

  6. The advanced neutron source

    International Nuclear Information System (INIS)

    Hayter, J.B.

    1994-01-01

    The Advanced Neutron Source (ANS), slated for construction start in 1994, will be a multipurpose neutron research laboratory serving academic and industrial users in chemistry, biology, condensed matter physics, nuclear and fundamental physics, materials science and engineering, and many other fields. It will be centered on the world's highest flux neutron beam reactor, operating at 330 MW, with careful design integration between the neutron source and the experiment systems. Many instruments will be situated in low backgrounds at distances up to 80 m from the reactor, using neutron guides with tailored neutron optical coatings for beam transport. Apart from the many stations for neutron scattering research, specialized stations will also be provided for isotope separation on-line, experiments with liquid hydrogen targets, neutron optical techniques such as interferometry, activation analysis, depth profiling, and positron production. Careful consideration has been given to providing a good research environment for visiting scientists, including easy access to the experimental areas, while maintaining a highly secure nuclear facility. This paper will describe the reactor and experimental facilities and give some examples of the types of research for which ANS has been designed

  7. Compact neutron generator

    Science.gov (United States)

    Leung, Ka-Ngo; Lou, Tak Pui

    2005-03-22

    A compact neutron generator has at its outer circumference a toroidal shaped plasma chamber in which a tritium (or other) plasma is generated. A RF antenna is wrapped around the plasma chamber. A plurality of tritium ion beamlets are extracted through spaced extraction apertures of a plasma electrode on the inner surface of the toroidal plasma chamber and directed inwardly toward the center of neutron generator. The beamlets pass through spaced acceleration and focusing electrodes to a neutron generating target at the center of neutron generator. The target is typically made of titanium tubing. Water is flowed through the tubing for cooling. The beam can be pulsed rapidly to achieve ultrashort neutron bursts. The target may be moved rapidly up and down so that the average power deposited on the surface of the target may be kept at a reasonable level. The neutron generator can produce fast neutrons from a T-T reaction which can be used for luggage and cargo interrogation applications. A luggage or cargo inspection system has a pulsed T-T neutron generator or source at the center, surrounded by associated gamma detectors and other components for identifying explosives or other contraband.

  8. Development of Neutron Spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chang Hee; Lee, J. S.; Seong, B. S. (and others)

    2007-06-15

    Neutron spectrometers which are used in the basic researches such as physics, chemistry and materials science and applied in the industry were developed at the horizontal beam port of HANARO reactor. In addition, the development of core components for neutron scattering and the upgrade of existing facilities are also performed. The vertical neutron reflectometer was fabricated and installed at ST3 beam port. The performance test of the reflectometer was completed and the reflectometer was opened to users. The several core parts and options were added in the polarized neutron spectrometer. The horizontal neutron reflectometer from Brookhaven National Laboratory was moved to HANARO and installed, and the performance of the reflectometer was examined. The HIPD was developed and the performance test was completed. The base shielding for TAS was fabricated. The soller collimator, Cu mosaic monochromator, Si BPC monochromator and position sensitive detector were developed and applied in the neutron spectrometer as part of core component development activities. In addition, the sputtering machine for mirror device are fabricated and the neutron mirror is made using the sputtering machine. The FCD was upgraded and the performance of the FCD are improved over the factor of 10. The integration and upgrade of the neutron detection system were also performed.

  9. Synovectomy by Neutron capture

    International Nuclear Information System (INIS)

    Vega C, H.R.; Torres M, C.

    1998-01-01

    The Synovectomy by Neutron capture has as purpose the treatment of the rheumatoid arthritis, illness which at present does not have a definitive curing. This therapy requires a neutron source for irradiating the articulation affected. The energy spectra and the intensity of these neutrons are fundamental since these neutrons induce nuclear reactions of capture with Boron-10 inside the articulation and the freely energy of these reactions is transferred at the productive tissue of synovial liquid, annihilating it. In this work it is presented the neutron spectra results obtained with moderator packings of spherical geometry which contains in its center a Pu 239 Be source. The calculations were realized through Monte Carlo method. The moderators assayed were light water, heavy water base and the both combination of them. The spectra obtained, the average energy, the neutron total number by neutron emitted by source, the thermal neutron percentage and the dose equivalent allow us to suggest that the moderator packing more adequate is what has a light water thickness 0.5 cm (radius 2 cm) and 24.5 cm heavy water (radius 26.5 cm). (Author)

  10. Neutron filters for producing monoenergetic neutron beams

    International Nuclear Information System (INIS)

    Harvey, J.A.; Hill, N.W.; Harvey, J.R.

    1982-01-01

    Neutron transmission measurements have been made on high-purity, highly-enriched samples of 58 Ni (99.9%), 60 Ni (99.7%), 64 Zn (97.9%) and 184 W (94.5%) to measure their neutron windows and to assess their potential usefulness for producing monoenergetic beams of intermediate energies from a reactor. Transmission measurements on the Los Alamos Sc filter (44.26 cm Sc and 1.0 cm Ti) have been made to determine the characteristics of the transmitted neutron beam and to measure the total cross section of Sc at the 2.0 keV minimum. When corrected for the Ti and impurities, a value of 0.35 +- 0.03 b was obtained for this minimum

  11. Machine for compacting solid residues

    International Nuclear Information System (INIS)

    Herzog, J.

    1981-11-01

    Machine for compacting solid residues, particularly bulky radioactive residues, constituted of a horizontally actuated punch and a fixed compression anvil, in which the residues are first compacted horizontally and then vertically. Its salient characteristic is that the punch and the compression anvil have embossments on the compression side and interpenetrating plates in the compression position [fr

  12. Neutron Stars and Pulsars

    CERN Document Server

    Becker, Werner

    2009-01-01

    Neutron stars are the most compact astronomical objects in the universe which are accessible by direct observation. Studying neutron stars means studying physics in regimes unattainable in any terrestrial laboratory. Understanding their observed complex phenomena requires a wide range of scientific disciplines, including the nuclear and condensed matter physics of very dense matter in neutron star interiors, plasma physics and quantum electrodynamics of magnetospheres, and the relativistic magneto-hydrodynamics of electron-positron pulsar winds interacting with some ambient medium. Not to mention the test bed neutron stars provide for general relativity theories, and their importance as potential sources of gravitational waves. It is this variety of disciplines which, among others, makes neutron star research so fascinating, not only for those who have been working in the field for many years but also for students and young scientists. The aim of this book is to serve as a reference work which not only review...

  13. Fast neutrons dosimetry

    International Nuclear Information System (INIS)

    Rzyski, B.M.

    1977-01-01

    A proton recoil technique has been developed for inducing thermoluminescence with incident fast neutrons. CaF 2 was used as the TL phosphor, and cane sugar and polyethylene were used as proton radiators. The phosphor and the hydrogeneous material powders were well mixed, encapsulated in glass tubes and exposed to Am-Be sources, resulting in recoils from incident fast neutrons of energy between 0,25 and 11,25 MeV. The intrinsic response of pure CaF 2 to fast neutrons without a hydrogeneous radiator was checked by using LiF (TLD-700). Glow curves were recorded from room temperature up to 350 0 C after different doses of neutrons and gamma rays of 60 Co. First collision dose due to fast neutrons in tissue like materials such as cane sugar and polyethylene was also calculated [pt

  14. Diffuse scattering of neutrons

    International Nuclear Information System (INIS)

    Novion, C.H. de.

    1981-02-01

    The use of neutron scattering to study atomic disorder in metals and alloys is described. The diffuse elastic scattering of neutrons by a perfect crystal lattice leads to a diffraction spectrum with only Bragg spreads. the existence of disorder in the crystal results in intensity and position modifications to these spreads, and above all, to the appearance of a low intensity scatter between Bragg peaks. The elastic scattering of neutrons is treated in this text, i.e. by measuring the number of scattered neutrons having the same energy as the incident neutrons. Such measurements yield information on the static disorder in the crystal and time average fluctuations in composition and atomic displacements [fr

  15. A Neutron Rem Counter

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, I Oe; Braun, J

    1964-01-15

    A neutron detector is described which measures the neutron dose rate in rem/h independently of the energy of the neutrons from thermal to 15 MeV. The detector consists of a BF{sub 3} proportional counter surrounded by a shield made of polyethylene and boron plastic that gives the appropriate amount of moderation and absorption to the impinging neutrons to obtain rem response. Two different versions have been developed. One model can utilize standard BF{sub 3} counters and is suitable for use in installed monitors around reactors and accelerators and the other model is specially designed for use in a portable survey instrument. The neutron rem counter for portable instruments has a sensitivity of 2.4 cps/mrem/h and is essentially nondirectional in response. With correct bias setting the counter is insensitive to gamma exposure up to 200 r/h from Co-60.

  16. Simulated workplace neutron fields

    International Nuclear Information System (INIS)

    Lacoste, V.; Taylor, G.; Rottger, S.

    2011-01-01

    The use of simulated workplace neutron fields, which aim at replicating radiation fields at practical workplaces, is an alternative solution for the calibration of neutron dosemeters. They offer more appropriate calibration coefficients when the mean fluence-to-dose equivalent conversion coefficients of the simulated and practical fields are comparable. Intensive Monte Carlo modelling work has become quite indispensable for the design and/or the characterization of the produced mixed neutron/photon fields, and the use of Bonner sphere systems and proton recoil spectrometers is also mandatory for a reliable experimental determination of the neutron fluence energy distribution over the whole energy range. The establishment of a calibration capability with a simulated workplace neutron field is not an easy task; to date only few facilities are available as standard calibration fields. (authors)

  17. Quadratic residues and non-residues selected topics

    CERN Document Server

    Wright, Steve

    2016-01-01

    This book offers an account of the classical theory of quadratic residues and non-residues with the goal of using that theory as a lens through which to view the development of some of the fundamental methods employed in modern elementary, algebraic, and analytic number theory. The first three chapters present some basic facts and the history of quadratic residues and non-residues and discuss various proofs of the Law of Quadratic Reciprosity in depth, with an emphasis on the six proofs that Gauss published. The remaining seven chapters explore some interesting applications of the Law of Quadratic Reciprocity, prove some results concerning the distribution and arithmetic structure of quadratic residues and non-residues, provide a detailed proof of Dirichlet’s Class-Number Formula, and discuss the question of whether quadratic residues are randomly distributed. The text is a valuable resource for graduate and advanced undergraduate students as well as for mathematicians interested in number theory.

  18. 2010 Neutron Review: ORNL Neutron Sciences Progress Report

    International Nuclear Information System (INIS)

    Bardoel, Agatha A.; Counce, Deborah Melinda; Ekkebus, Allen E.; Horak, Charlie M.; Nagler, Stephen E.; Kszos, Lynn A.

    2011-01-01

    chalcogenides), a class of materials discovered in 2008. This research is yielding new insights into the relationship between magnetism and superconductivity and has established several key features of this family of high-temperature superconducting (HTS ) materials: the maximum magnetic field at which they can function, the nature of the electrons involved in the superconductivity, the dependence of the properties upon chemical substitution, and the character of the magnetic fluctuations in the material. The results suggest that despite important differences between these materials and the HTS copper oxides, a universal mechanism may be responsible for the unconventional superconductivity. (4) Coal Sequestration Research: A New Home for Greenhouse Gases - One possibility for slowing down the increasing levels of carbon dioxide (CO 2 ) in the atmosphere is to capture the gas in natural underground features such as coal seams. Critical to the feasibility of this technology is determining how much CO 2 can be stored, no method for which has been found - until now. (5) Accelerator Reliability Passes 92% - In December 2010, SNS set a new record for itself when the accelerator ran at 1 MW with 100% reliability. Target Performance Exceeds All Expectations - The mercury target used at SNS is the first of its kind. During the design and planning for SNS, many people were skeptical that the target would work. In 2010, it was confirmed that the target was working not only well but much better than anyone would have imagined. (6) Changing the World of Data Acquisition - Researchers at SNS are starting to benefit from event-based data analysis. Event data mode captures and stores an individual data set for every single neutron that strikes a detector - precisely when and where the neutron is detected. This technique provides numerous advantages over traditional methods. Event data mode allows researchers to process their data at the highest resolution possible with no loss of data. This

  19. 2010 Neutron Review: ORNL Neutron Sciences Progress Report

    Energy Technology Data Exchange (ETDEWEB)

    Bardoel, Agatha A [ORNL; Counce, Deborah M [ORNL; Ekkebus, Allen E [ORNL; Horak, Charlie M [ORNL; Nagler, Stephen E [ORNL; Kszos, Lynn A [ORNL

    2011-06-01

    pnictides and chalcogenides), a class of materials discovered in 2008. This research is yielding new insights into the relationship between magnetism and superconductivity and has established several key features of this family of high-temperature superconducting (HTS ) materials: the maximum magnetic field at which they can function, the nature of the electrons involved in the superconductivity, the dependence of the properties upon chemical substitution, and the character of the magnetic fluctuations in the material. The results suggest that despite important differences between these materials and the HTS copper oxides, a universal mechanism may be responsible for the unconventional superconductivity. (4) Coal Sequestration Research: A New Home for Greenhouse Gases - One possibility for slowing down the increasing levels of carbon dioxide (CO{sub 2}) in the atmosphere is to capture the gas in natural underground features such as coal seams. Critical to the feasibility of this technology is determining how much CO{sub 2} can be stored, no method for which has been found - until now. (5) Accelerator Reliability Passes 92% - In December 2010, SNS set a new record for itself when the accelerator ran at 1 MW with 100% reliability. Target Performance Exceeds All Expectations - The mercury target used at SNS is the first of its kind. During the design and planning for SNS, many people were skeptical that the target would work. In 2010, it was confirmed that the target was working not only well but much better than anyone would have imagined. (6) Changing the World of Data Acquisition - Researchers at SNS are starting to benefit from event-based data analysis. Event data mode captures and stores an individual data set for every single neutron that strikes a detector - precisely when and where the neutron is detected. This technique provides numerous advantages over traditional methods. Event data mode allows researchers to process their data at the highest resolution possible

  20. Lattice strain measurements on sandstones under load using neutron diffraction

    Science.gov (United States)

    Frischbutter, A.; Neov, D.; Scheffzük, Ch.; Vrána, M.; Walther, K.

    2000-11-01

    Neutron diffraction methods (both time-of-flight- and angle-dispersive diffraction) are applied to intracrystalline strain measurements on geological samples undergoing uniaxial increasing compressional load. The experiments were carried out on Cretaceous sandstones from the Elbezone (East Germany), consisting of >95% quartz which are bedded but without crystallographic preferred orientation of quartz. From the stress-strain relation the Young's modulus for our quartz sample was determined to be (72.2±2.9) GPa using results of the neutron time-of-flight method. The influence of different kinds of bedding in sandstones (laminated and convolute bedding) could be determined. We observed differences of factor 2 (convolute bedding) and 3 (laminated bedding) for the elastic stiffness, determined with angle dispersive neutron diffraction (crystallographic strain) and with strain gauges (mechanical strain). The data indicate which geological conditions may influence the stress-strain behaviour of geological materials. The influence of bedding on the stress-strain behaviour of a laminated bedded sandstone was indicated by direct residual stress measurements using neutron time-of-flight diffraction. The measurements were carried out six days after unloading the sample. Residual strain was measured for three positions from the centre to the periphery and within two radial directions of the cylinder. We observed that residual strain changes from extension to compression in a different manner for two perpendicular directions of the bedding plane.