Neutron scattering lengths and cross sections of the barium isotopes

1985 ◽  
Vol 322 (1) ◽  
pp. 105-113 ◽  
Author(s):  
L. Koester ◽  
K. Knopf ◽  
W. Waschkowski
Keyword(s):  
Neutron Scattering ◽  
Cross Sections ◽  
Scattering Lengths

Neutron scattering lengths and cross sections

Neutron News ◽  
1992 ◽  
Vol 3 (3) ◽  
pp. 26-37 ◽  
Author(s):  
Varley F. Sears
Keyword(s):  
Neutron Scattering ◽  
Cross Sections ◽  
Scattering Lengths

Wechselwirkung von Neutronen mit Wolfram und seinen Isotopen

1987 ◽  
Vol 42 (9) ◽  
pp. 909-916 ◽  
Author(s):  
K. Knopf ◽  
W. Waschkowski
Keyword(s):  
Neutron Scattering ◽  
Cross Sections ◽  
Coherent Scattering ◽  
Total Cross Sections ◽  
Resonance Parameters ◽  
Scattering Lengths

The coherent neutron scattering lengths and total cross sections of elemental and oxide samples of natural and isotopically enriched W are determined. From these results the following coherent scattering lengths, b, and absorptions at 0.0253 eV, σγ were deduced:b (natW) = 4.86±0.02 fm, σγ = 17.3 ±0.5 b ,b (182W) = 7.04±0.04 fm, σγ = 19.6±0.3 b ,b (183W) = 6.59±0.04 fm, σγ = 10.5±0.2 b ,b (184W) = 7.55±0.06 fm, σγ = 1.7±0.1 b ,b (186W) = -0 .7 3±0.04 fm, σγ = 38.5 ±0.8 b .By comparison with the resonance parameters, the incoherence and the potential radii are derived and discussed. The bound level on W-182 must be fitted with a scattering width of gI0n = 161 meV at E0 = - 94 eV.

Neutron scattering length determination by means of total scattering

2018 ◽  
Vol 51 (3) ◽  
pp. 854-866 ◽  
Author(s):  
Alex C. Hannon ◽  
Alexandra S. Gibbs ◽  
Hidenori Takagi
Keyword(s):  
Correlation Function ◽  
Neutron Diffraction ◽  
Neutron Scattering ◽  
Cross Sections ◽  
Scattering Length ◽  
Neutron Diffraction Pattern ◽  
Average Density ◽  
A Value ◽  
Oxide Crystal ◽  
Scattering Lengths

A new method for the measurement of bound coherent neutron scattering lengths is reported. It is shown that a relative measurement of the neutron scattering length, {\overline b}, of an element can be made by analysis of the neutron correlation function of a suitable oxide crystal powder. For this analysis, it is essential to take into account the average density contribution to the correlation function, as well as the contributions arising from distances between atoms in the crystal. The method is demonstrated and verified by analysis of the neutron correlation function for the corundum form of Al2O3, yielding a value {\overline b} = 3.44 (1) fm for Al, in good agreement with the literature. The method is then applied to the isotopes of iridium, for which the values of the scattering lengths were unknown, and which are difficult to investigate by other methods owing to the large cross sections for the absorption of neutrons. The neutron correlation function of a sample of Sr2IrO4 enriched in 193Ir is used to determine values {\overline b} = 9.71 (18) fm and {\overline b} = 12.1 (9) fm for 193Ir and 191Ir, respectively, and these are consistent with the tabulated scattering length and cross sections of natural Ir. These values are of potential application for obtaining improved neutron diffraction results on iridates by the use of samples enriched in 193Ir, so that the severe absorption problems associated with 191Ir are avoided. Rietveld refinement of the neutron diffraction pattern of isotopically enriched Sr2IrO4 is used to yield a similar result for Ir. However, in practice the Rietveld result is shown to be less reliable because of correlation between the parameters of the fit.

Neutron Scattering Lengths and Cross Sections

2013 ◽  
pp. 471-528 ◽  
Author(s):  
Javier Dawidowski ◽  
José Rolando Granada ◽  
Javier Roberto Santisteban ◽  
Florencia Cantargi ◽  
Luis Alberto Rodríguez Palomino
Keyword(s):  
Neutron Scattering ◽  
Cross Sections ◽  
Scattering Lengths

Interaction of Slow Neutrons with Cobalt and Tin

1997 ◽  
Vol 52 (3) ◽  
pp. 270-278 ◽  
Author(s):  
K. Knopf ◽  
W. Waschkowski ◽  
A. Aleksejevs ◽  
S. Barkanova ◽  
J. Tambergs
Keyword(s):  
Neutron Scattering ◽  
Cross Sections ◽  
Optical Model ◽  
Coherent Scattering ◽  
Potential Scattering ◽  
Absorption Cross ◽  
Total Cross Sections ◽  
Scattering Lengths ◽  
Thermal Absorption

AbstractCoherent neutron scattering lengths and total cross sections have been measured on samples of Co, Sn and on isotopically enriched Sn-oxides. The following data were obtained: • the coherent scattering lengths (in fm) of the bound atoms 59Co (2.49 ± 0.02), natSn (6.22 ± 0.01) 116Sn (6.10 ± 0.01), 117Sn (6.59 ± 0.08), 118Sn (6.23 ± 0.04), 119Sn (6.28 ± 0.03), 120Sn (6.67 ± 0.04), 122Sn (5.93 ± 0.03), and 124Sn(6.15 ± 0.03); • the thermal absorption cross sections (in b) natSn (0.569 ± 0.005), 116Sn (0.50 ± 0.03), 117Sn (0.77 ± 0.06), 118Sn (0.24 ± 0.06), 119Sn (2.19 ± 0.06), 120Sn (0.55 ± 0.06), 122Sn (0.19 ± 0.06), and 124Sn (0.43 ± 0.06). New bound levels were evaluated for the investigated nuclei. In combination with the resonance parameters the measured scattering lengths allowed the determination of potential scattering radii R' which are of particular interest for the check of the optical model.

Neutron diffraction, inelastic scattering and the structure of amphiphiles and macromolecules in solution

1975 ◽  
Vol 345 (1640) ◽  
pp. 119-144 ◽  
Keyword(s):  
Neutron Diffraction ◽  
Inelastic Scattering ◽  
Cross Sections ◽  
Biological Molecules ◽  
Variation Method ◽  
Contrast Variation ◽  
Structure And Dynamics ◽  
Spin Resonance ◽  
Scattering Lengths ◽  
Scattering Cross Sections

The methods by which neutron diffraction and inelastic scattering may be used to study the structure and dynamics of solutions are reviewed, with particular reference to solutions of amphiphile and biological molecules in water. Neutron methods have particular power because the scattering lengths for protons and deuterons are of opposite sign, and hence there exists the possibility of obtaining variable contrast between the scattering of the aqueous medium and the molecules in it. In addition, the contrast variation method is also applicable to inelastic scattering studies whereby the dynamics of one component of the solution can be preferentially studied due to large and variable differences in the scattering cross sections. Both applications of contrast variation are illustrated with examples of amphiphile-water lamellar mesophases, diffraction from collagen, viruses, and polymer solutions. Inelastic scattering observations and the dynamics of water between the lamellar sheets allow microscopic measurements of the water diffusion along and perpendicular to the layers. The information obtained is complementary to that from nuclear magnetic resonance and electron spin resonance studies of diffusion.

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