Investigation of multiple ultrasmall-angle neutron scattering with the aid of a double-crystal diffractometer

2014 ◽  
Vol 77 (10) ◽  
pp. 1187-1202 ◽  
Author(s):  
Yu. G. Abov ◽  
F. S. Dzheparov ◽  
N. O. Elyutin ◽  
D. V. Lvov ◽  
A. N. Tyulyusov
Keyword(s):  
Neutron Scattering ◽  
Double Crystal ◽  
Double Crystal Diffractometer

Absolute Calibration of Small-Angle Neutron Scattering Data of a Double-Crystal Diffractometer

1997 ◽  
Vol 30 (5) ◽  
pp. 857-861 ◽  
Author(s):  
F. Carsughi ◽  
D. Bellmann ◽  
J. Kulda ◽  
M. Magnani ◽  
M. Stefanon
Keyword(s):  
Neutron Scattering ◽  
Cross Section ◽  
Cross Sections ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Scattering Data ◽  
Absolute Calibration ◽  
Double Crystal ◽  
Similar Materials ◽  
Double Crystal Diffractometer

Small-angle neutron scattering (SANS) experiments generally provide the absolute SANS cross sections and this allows quantitative results to be obtained; however, data collected at double-crystal diffractometers are frequently not normalized to absolute cross sections and they are used only for qualitative analysis. In point-geometry diffractometers, the normalization is done by comparing the scattered intensities to those of samples of known cross sections or by measuring the direct-beam intensity; in the double-crystal diffractometer, the incident flux information is contained in the rocking curve measured without a sample and this feature can therefore be used to normalize the scattered intensities to the SANS cross sections. A sample of thickness 1 mm of the Ni-based superalloy UDIMET 520 was analyzed at a double-crystal diffractometer; the SANS cross section obtained by the proposed procedure compares well with the SANS cross section found for similar materials by using conventional point-geometry diffractometers and calibrated by light water.

scholarly journals Ultra-small-angle neutron scattering with azimuthal asymmetry

2016 ◽  
Vol 49 (3) ◽  
pp. 934-943 ◽  
Author(s):  
X. Gu ◽  
D. F. R. Mildner
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Incident Beam ◽  
Bedding Plane ◽  
Double Crystal ◽  
Thin Sections ◽  
Wide Range ◽  
Sans Data ◽  
Double Crystal Diffractometer

Small-angle neutron scattering (SANS) measurements from thin sections of rock samples such as shales demand as great a scattering vector range as possible because the pores cover a wide range of sizes. The limitation of the scattering vector range for pinhole SANS requires slit-smeared ultra-SANS (USANS) measurements that need to be converted to pinhole geometry. The desmearing algorithm is only successful for azimuthally symmetric data. Scattering from samples cut parallel to the plane of bedding is symmetric, exhibiting circular contours on a two-dimensional detector. Samples cut perpendicular to the bedding show elliptically dependent contours with the long axis corresponding to the normal to the bedding plane. A method is given for converting such asymmetric data collected on a double-crystal diffractometer for concatenation with the usual pinhole-geometry SANS data. The aspect ratio from the SANS data is used to modify the slit-smeared USANS data to produce quasi-symmetric contours. Rotation of the sample about the incident beam may result in symmetric data but cannot extract the same information as obtained from pinhole geometry.

The Use of a Multi-Double-Crystal Diffractometer to Investigate Nickel Domains

1997 ◽  
Vol 30 (5) ◽  
pp. 849-853 ◽  
Author(s):  
W. Treimer ◽  
A. Höfer ◽  
H. Strothmann
Keyword(s):  
Single Crystals ◽  
Domain Structure ◽  
Small Angle ◽  
Angular Resolution ◽  
Main Peak ◽  
High Angular Resolution ◽  
Bloch Wall ◽  
Double Crystal ◽  
First Results ◽  
Double Crystal Diffractometer

The investigations of the domain structure in Ni single crystals is best performed with a double-crystal diffractometer. Conventional small-angle instruments do not have the necessary angular resolution to distinguish satellites of a main peak due to spin-dependent refraction of unpolarized neutrons by Bloch walls in Ni. With the help of a double-crystal diffractometer operating with lamellae crystals as monochromator and analyzer, the angular resolution is maintained but the intensity enhanced by a factor of 5.4. Within a series of measurements, it was possible to investigate Ni domains due to the high angular resolution of the new multi-double-crystal instrument and this improved intensity. The first results of the domain structure in (110) Ni single crystals and a good estimation of the Bloch wall thickness are given.

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