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SB3. Experiment on secondary gamma-ray production cross sections averaged over a fast-neutron spectrum for each of 13 different elements plus a stainless steel

Description: The experimental and calculational details for a CSEWG integral data testing shielding experiment are presented. This particular experiment measured the secondary gamma-ray production cross sections averaged over a fast-neutron spectrum for iron, oxygen, sodium, aluminum, copper, titanium, calcium, potassium, silicon, nickel, zinc, barium, sulfur, and a type 321 stainless steel. The gamma-ray production cross sections were binned into 0.5-MeV wide gamma-ray energy intervals. 29 tables, 1 figure (auth)
Date: January 1, 1976
Creator: Maerker, R.E.
Partner: UNT Libraries Government Documents Department

Recent measurements of neutron total cross sections on a wide range of targets from 5 to 600 MeV at LANSCE/WNR

Description: We have completed a new set of total cross section measurements, snd have measured approximately 36 additional samples. The goal of the new measurements was 1% statistical accuracy in 1% energy bins with systematic errors less than 1%. This was achieved for all but the smallest samples, for which the statistical accuracy was as large as 2% in 1% bins. However, the energy resolution is significantly better than this at low energies. The samples were: * The APT spallation target material: W * Medium-mass stmctural materials: Ti, V, Cr, Mn, Fe, Co, Ni * Actinides: Th, depleted U * Other materials for global optical model development: F, Mg, P, S, K, Y, Mo, In, Au, Hg, natural Pb * Separated isotopes of light nuclei: {sup 6}Li%, {sup 7}Li, {sup 10}B, {sup 11}B, {sup 13}C, * Medium- and heavy-mass separated isotopes: {sup 54,56}Fe, {sup 182,183,184,186}W * Few-nucleon physics: H, D.
Date: May 1, 1997
Creator: Dietrich, F.S.; Abfalterer, W.P.; Haight, R.C.; Morgan, G.L.; Bateman, F.B. & Finlay, R.W.
Partner: UNT Libraries Government Documents Department

Delayed neutron data: review and evaluation

Description: BS>The status of delayed neutron measurements is reviewed. Emphasis is placed on the absolute yield va the energy of the neutrons cauging fission, group yields and periods, and in the delayed neutron spectra. Systematics are discussed; and an evaluated data set, based both on available measurements and on systematics arguments, is suggested for inclusion in ENDF/B-IV. Areas of delayed neutron studies which require additional measurements are outlined. (18 figures, 18 tables) (auth)
Date: April 1, 1974
Creator: Cox, S.A.
Partner: UNT Libraries Government Documents Department

SB2. Experiment on secondary gamma-ray production cross sections arising from thermal-neutron capture in each of 14 different elements plus a stainless steel

Description: The experimental and calculational details for a CSEWG integral data testing shielding experiment are presented. This particular experiment measured the secondary gamma-ray production cross sections arising from thermal-neutron capture in iron, nitrogen, sodium, aluminum, copper, titanium, calcium, potassium, chlorine, silicon, ickel, zinc, barium, sulfur and a type 321 stainless steel. 1 figure, 30 tables (auth)
Date: January 1, 1976
Creator: Maerker, R.E.
Partner: UNT Libraries Government Documents Department

Cross-section sensitivity of tritium breeding in fusion reactor blankets

Description: ion; San Diego, California, USA (16 Apr 1974). The objective of the present study is the identification of crosssection uncertainties which might produce uncertainties of the order of several percent in the tritium breeding ratio in fusion reactor blankets. The model chosen was the bench-mark configuuration specified at the Neutronics Session of the International Working Sessions on Fusion Reactor Technology. Using ENDF/B version 3 cross sections and an S/sub 4/- P/sub 3/ transport calculation, calculations of the effects of substantial cross section changes were performed both individually and in selected pairs which would leave the total cross section of an isotope unchanged. The cross sections most worth further study were the /sup 7/Li(n,n' alpha )t, the /sup 93/Nb (n,2n) and (n,n') reactions. (auth)
Date: January 1, 1973
Creator: Tobias, M. & Steiner, D.
Partner: UNT Libraries Government Documents Department

Nuclear structure studies with the inelastic neutron scattering rection and gamma-ray detection

Description: The (<i>n</i>, <i>n</i>ยด(gamma)) reaction has been used at the University of Kentucky accelerator facility to examine the detailed structure of a number of nuclei. The advantages of this method are reviewed, and recent developments are described. Examples of unique nuclear structure studies that have been carried out with this method are presented.
Date: December 10, 1998
Creator: Garrett, P. E.; Warr, N. & Yates, S. W.
Partner: UNT Libraries Government Documents Department

A description of NUEXS, an upgrade of the code FCUP used to compute proton recoil current from CH{sub 2} foils

Description: A computer code, FCUP, developed by A. Craft computes currents of recoil protons from a time- and energy-dependent neutron flux striking a CH{sub 2} foil. Three problem areas need to be addressed to extend the code`s usefulness. First, FCUP computes a response that is not time dependent; that is, only the input time bin is broadened to account for the finite time distribution of protons from a single neutron energy; second, the time coordinate of the signal predicted is translated arbitrarily rather than absolutely relative to the time of maximum neutron production in the source; and third, the code does not account for electron pickup by protons at low proton energies in the target and absorber foils. This report describes the changes in calculational method used to overcome these problems.
Date: August 1, 1982
Creator: Stelts, M.L. & Wood, B.E.
Partner: UNT Libraries Government Documents Department

Polarization Dependence of the Spin-Density-Wave Excitations in Single-Domain Chromium

Description: A polarised neutron scattering experiment has been performed on a single-Q, single domain sample of Cr in a magnetic field of 4 T in the transverse spin-density-wave phase. It is confirmed that the longitudinal fluctuations are enhanced for energy transfers E {lt} 8 meV similarly as in the longitudinal spin-density-wave phase. The spin wave modes with deltaS parallel and perpendicular to Q are isotropic within the E-range investigated.
Date: December 31, 1997
Creator: Boeni, P.; Sternlieb, B.J.; Shirane, G.; Roessli, B.; Werner, S.A. & Lorenzo, J.E.
Partner: UNT Libraries Government Documents Department

Survey of experimentally determined neutron cross sections of the actinides

Description: Experimentally determined neutron cross section data for heavy actinides involved in the reactor production chains leading to /sup 238/Pu and /sup 252/Cf were examined. The neutron energy region below one kilovolt is emphasized because these cross sections and reactions are important for thermal and near- thermal reactors. Included with the data summaries are brief descriptions of pertinent measurements in progress or plarmed for the near future at United States and European laboratories. Additional measurements that are needed are suggested. Of most immediate interest are: sigma /sub ny/ for /sup 248/Cm below 1 keV, sigma /sub nf/ for /sup 245/Cm below 40 eV, sigma /sub nf/ for /sup 247/ Cm below 40 eV, and sigma /sub nf/ for /sup 251/Cf below 1 keV. Data were gathered for the survey through January 1973. (auth)
Date: December 1, 1973
Creator: Benjamin, R.W.
Partner: UNT Libraries Government Documents Department

$sup 63$Cu and $sup 65$Cu neutron elastic and inelastic scattering cross sections from 5.50 to 8.50 MeV

Description: Measured neutron elastic and inelastic scattering cross sections for / sup 63/Cu and /sup 65/Cu between 5.50 and 8.50 MeV are presented and compared with elastic data of Holmqvist and Wiedling and with ENDF/B III MAT 1085 and 1086. The elastic differential cross sections are in fair agreement with those of Holmqvist and Wiedling in shape. The angle-integrated differential elastic cross sections are systematically higher by as much as 28% than those of Holmqvist and Wiedling above 5 MeV, a situation similar to that found in comparing the two sets of data for other elements. ENDF/B III MAT 1085 and 1086 angular distributions underestimate the elastic forward peak below 20 deg. when compared with experimental results and display unphysical fluctuations due to the use of a Legendre series of order 20 where order 9 is the highest required by the data. An evaporation model with temperature ranging from 0.8 to 1.05 MeV reasonably describes inelastic scattering to levels in the residual copper nuclei of excitation energy above 3.2 MeV. (auth)
Date: February 1, 1974
Creator: Kinney, W.E. & Perey, F.G.
Partner: UNT Libraries Government Documents Department

Natural chromium and $sup 52$Cr neutron elastic and inelastic scattering cross sections from 4.07 to 8.56 MeV

Description: Measured neutron elastic and inelastic scattering cross sections for natural chromium between 4.07 and 8.56 MeV and for /sup 52/Cr between 6.44 and 8.56 MeV are presented and compared with the elasti c differertial cross sections of Holmqvist and Wiedling and with ENDF/B MAT 1121. The elastic scattering differertial cross sections are in fair agreemert with those of Holmqvist and Wiedling. The angle-integrated differertial elastic scattering cross sections are systematically higher by as much as 17% than those of Holmqvist and Wiedling above 4.6 MeV, a situation simtlar to that found in comparing the two sets of data for other elemerts. The ENDF/B III MAT 1121 elastic angnlar distributions are found to be in poor agreement with experimental results from 4 to 8.5 MeV, though the ENDF/B III MAT 1121 angleintegrated differenti al elastic scattering cross sections agree within experimental uncertainties with the results over this energy range. An evaporation model of inelastic scattering is found to be of questionable validity if applied to levels in the residual,nucleus of excitation energy less than 6 MeV. (auth)
Date: January 1, 1974
Creator: Kinney, W. E. & Perey, F. G.
Partner: UNT Libraries Government Documents Department

Analysis of magnetic neutron scattering data

Description: The determination of the proper magnetic form factors for use in the analysis of diffuse-scattering data is discussed, and that information which is immediately available from such data is considered. Apparent discrepancies between the results of diffuse scattering and diffraction experiments on ferromagnetic Ni-Cu alloys are resolved. It is shown that the data indicate that the negative spin density usually attributed to conduction electrons instead arises largely from the overlap of localized wavefunctions, as was first suggested by Moon. 3 figures. (auth)
Date: December 1, 1975
Creator: Felcher, G.; Garland, J.W.; Cable, J.W. & Medina, R.
Partner: UNT Libraries Government Documents Department