Scattering studies of large scale structures at the ultra small angle neutron scattering instrument S18

2002 ◽  
Vol 304 (1-2) ◽  
pp. 220-229 ◽  
Author(s):  
M. Hainbuchner ◽  
M. Baron ◽  
F. Lo Celso ◽  
A. Triolo ◽  
R. Triolo ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Large Scale ◽  
Large Scale Structures ◽  
Scale Structures

scholarly journals The suite of small-angle neutron scattering instruments at Oak Ridge National Laboratory

2018 ◽  
Vol 51 (2) ◽  
pp. 242-248 ◽  
Author(s):  
William T. Heller ◽  
Matthew Cuneo ◽  
Lisa Debeer-Schmitt ◽  
Changwoo Do ◽  
Lilin He ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Large Scale ◽  
National Laboratory ◽  
High Flux ◽  
Oak Ridge ◽  
Large Scale Structures ◽  
Oak Ridge National Laboratory ◽  
Scale Structures

Oak Ridge National Laboratory is home to the High Flux Isotope Reactor (HFIR), a high-flux research reactor, and the Spallation Neutron Source (SNS), the world's most intense source of pulsed neutron beams. The unique co-localization of these two sources provided an opportunity to develop a suite of complementary small-angle neutron scattering instruments for studies of large-scale structures: the GP-SANS and Bio-SANS instruments at the HFIR and the EQ-SANS and TOF-USANS instruments at the SNS. This article provides an overview of the capabilities of the suite of instruments, with specific emphasis on how they complement each other. A description of the plans for future developments including greater integration of the suite into a single point of entry for neutron scattering studies of large-scale structures is also provided.

DCD USANS and SESANS: a comparison of two neutron scattering techniques applicable for the study of large-scale structures

2013 ◽  
Vol 46 (2) ◽  
pp. 354-364 ◽  
Author(s):  
Christine Rehm ◽  
John Barker ◽  
Wim G. Bouwman ◽  
Roger Pynn
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Large Scale ◽  
Bragg Reflection ◽  
Spin Echo ◽  
Double Crystal ◽  
Large Scale Structures ◽  
Silicon Crystals ◽  
Performance Gains

This paper provides a comparison of the capabilities of two techniques for extending the range of conventional small-angle neutron scattering (SANS) towards the micrometre length scale, namely the double-crystal diffraction ultra-small-angle neutron scattering (DCD USANS) technique, which uses perfect silicon crystals in Bragg reflection, and spin-echo SANS (SESANS), a method that uses the spin precessions of a polarized neutron beam. Both methods encode the scattering angle to very high precision. Based on round-robin test measurements, the strengths and weaknesses of the two techniques are discussed with respect to the measurement of the particle size of monodisperse scatterers, and potential performance gains for state-of-the-art DCD USANS and SESANS instruments are investigated.

Design and performance of the variable-wavelength Bonse–Hart ultra-small-angle neutron scattering diffractometer KOOKABURRA at ANSTO

2018 ◽  
Vol 51 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Christine Rehm ◽  
Liliana de Campo ◽  
Alain Brûlé ◽  
Frank Darmann ◽  
Friedl Bartsch ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Large Scale ◽  
Pyrolytic Graphite ◽  
Bragg Angle ◽  
Double Crystal ◽  
And Performance ◽  
Doubly Curved

The double-crystal ultra-small-angle neutron scattering (USANS) diffractometer KOOKABURRA at ANSTO was made available for user experiments in 2014. KOOKABURRA allows the characterization of microstructures covering length scales in the range of 0.1–10 µm. Use of the first- and second-order reflections coming off a doubly curved highly oriented mosaic pyrolytic graphite premonochromator at a fixed Bragg angle, in conjunction with two interchangeable pairs of Si(111) and Si(311) quintuple-reflection channel-cut crystals, permits operation of the instrument at two individual wavelengths, 4.74 and 2.37 Å. This unique feature among reactor-based USANS instruments allows optimal accommodation of a broad range of samples, both weakly and strongly scattering, in one sample setup. The versatility and capabilities of KOOKABURRA have already resulted in a number of research papers, clearly demonstrating that this instrument has a major impact in the field of large-scale structure determination.

scholarly journals Small angle neutron scattering contrast variation reveals heterogeneities of interactions in protein gels

Soft Matter ◽  
2016 ◽  
Vol 12 (24) ◽  
pp. 5340-5352 ◽  
Author(s):  
A. Banc ◽  
C. Charbonneau ◽  
M. Dahesh ◽  
M.-S. Appavou ◽  
Z. Fu ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Large Scale ◽  
Contrast Variation ◽  
Gluten Proteins ◽  
Protein Gels

The SANS analysis of gluten gels prepared with deuterated solvent evidences the formation of large scale zones enriched in protonated proteins. The formation of these zones is associated to the heterogeneities of interaction between the different gluten proteins and the solvent.

scholarly journals Small-angle neutron scattering (SANS) and spin-echo SANS measurements reveal the logarithmic fractal structure of the large-scale chromatin organization in HeLa nuclei

2019 ◽  
Vol 52 (4) ◽  
pp. 844-853 ◽  
Author(s):  
Ekaterina G. Iashina ◽  
Mikhail V. Filatov ◽  
Rimma A. Pantina ◽  
Elena Yu. Varfolomeeva ◽  
Wim G. Bouwman ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Large Scale ◽  
Fractal Structure ◽  
Water Solution ◽  
Spin Echo ◽  
High Surface ◽  
Chromatin Organization ◽  
Structural Level

This paper reports on the two-scale fractal structure of chromatin organization in the nucleus of the HeLa cell. Two neutron scattering methods, small-angle neutron scattering (SANS) and spin-echo SANS, are used to unambiguously identify the large-scale structure as being a logarithmic fractal with the correlation function γ(r) ∼ ln(r/ξ). The smaller-scale structural level is shown to be a volume fractal with dimension D F = 2.41. By definition, the volume fractal is self-similar at different scales, while the logarithmic fractal is hierarchically changed upon scaling. As a result, the logarithmic fractal is more compact than the volume fractal but still has a rather high surface area, which provides accessibility at all length scales. Apparently such bi-fractal chromatin organization is the result of an evolutionary process of optimizing the compactness and accessibility of gene packing. As they are in a water solution, the HeLa nuclei tend to agglomerate over time. The large-scale logarithmic fractal structure of chromatin provides the HeLa nucleus with the possibility of penetrating deeply into the adjacent nucleus during the agglomeration process. The interpenetration phenomenon of the HeLa nuclei shows that the chromatin-free space of one nucleus is not negligible but is as large as the volume occupied by chromatin itself. It is speculated that it is the logarithmic fractal architecture of chromatin that provides a comfortable compartment for this most important function of the cell.

Characterization of anisotropic pores and spatially oriented precipitates in sintered Mo-base alloys using small-angle neutron scattering

2018 ◽  
Vol 51 (6) ◽  
pp. 1706-1714 ◽  
Author(s):  
Lukas Karge ◽  
David Lang ◽  
Jürgen Schatte ◽  
Ralph Gilles ◽  
Sebastian Busch ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Large Scale ◽  
Anisotropic Scattering ◽  
Relative Volume ◽  
Processing Route ◽  
Alloy Matrix ◽  
Characterization Of Materials

Small-angle neutron scattering (SANS) is a powerful method for the characterization of materials in the mesoscopic size range. For example, the method can be used to investigate the precipitation mechanisms in powder metallurgically processed materials. As a result of the processing route, the alloy matrix is usually heavily textured. If precipitates have an orientation relationship to the alloy matrix, they can produce an anisotropic scattering pattern showing streaks. The scattering is superimposed by a background with ellipsoidal shape, originating from deformed large-scale structures. The evaluation of such data quickly becomes elaborate and a quantitative analysis of precipitation is difficult. The present work reports a method for treating the anisotropic scattering from such samples. A systematic study of the ellipsoidal background reveals that it originates from uniaxially deformed sinter pores. Irrespective of the degree of deformation during the processing route, SANS shows that sinter pores remain present in the matrix, and their morphology and relative volume fractions are determined. Consequently, their scattering signal can be subtracted to reveal the scattering from aligned precipitates. The method is demonstrated on powder metallurgically produced pure Mo and an Mo–Hf–C alloy.

Sign in / Sign up

Export Citation Format

Share Document