Comparison of Small-Angle Neutron Scattering of δ' Precipitation in an Al–Li Alloy at a High-Flux Reactor and at a Pulsed-Neutron Source

1997 ◽  
Vol 30 (5) ◽  
pp. 602-606 ◽  
Author(s):  
G. Albertini ◽  
F. Carsughi ◽  
R. Coppola ◽  
R. K. Heenan ◽  
M. Stefanon
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Size Distribution Function ◽  
Data Sets ◽  
Flux Reactor ◽  
Average Size ◽  
Pulsed Neutron ◽  
Pulsed Neutron Source ◽  
Good Agreement

Two different small-angle neutron scattering (SANS) facilities, the D11 camera at the Institut Laue–Langevin (ILL, Grenoble, France) and the LOQ time-of-flight diffractometer at the Rutherford Appleton Laboratory (RAL, Didcot, Oxon, England), were used in the investigations of δ′-Al3Li precipitation at 463 K in Al–Li 3% alloy. The results obtained from the steady-state reactor and from the pulsed source by using two different data-acquisition techniques and two different procedures for data analysis are compared. The SANS curves for the same set of samples investigated using the two different instruments are in good agreement within the experimental uncertainties. A check was also made on the metallurgically relevant quantities, namely the average size and the size-distribution function of the δ′ precipitates at the various stages of the ageing process, obtained from the two sets of SANS curves by applying the same numerical method. Good agreement was found between the results from the two data sets.

Polarization analysis for small-angle neutron scattering with a 3He spin filter at a pulsed neutron source

2021 ◽  
Vol 54 (2) ◽  
pp. 548-556
Author(s):  
Takuya Okudaira ◽  
Yuki Ueda ◽  
Kosuke Hiroi ◽  
Ryuhei Motokawa ◽  
Yasuhiro Inamura ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Neutron Source ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Incoherent Scattering ◽  
Polarization Analysis ◽  
Spin Filter ◽  
Scattering Intensity ◽  
Pulsed Neutron ◽  
Pulsed Neutron Source

Neutron polarization analysis (NPA) for small-angle neutron scattering (SANS) experiments using a pulsed neutron source was successfully achieved by applying a 3He spin filter as a spin analyzer for the neutrons scattered from the sample. The cell of the 3He spin filter gives a weak small-angle scattering intensity (background) and covers a sufficient solid angle for performing SANS experiments. The relaxation time of the 3He polarization is sufficient for continuous use for approximately 2 days, thus reaching the typical duration required for a complete set of SANS experiments. Although accurate evaluation of the incoherent neutron scattering, which is predominantly attributable to the extremely large incoherent scattering cross section of hydrogen atoms in samples, is difficult using calculations based on the sample elemental composition, the developed NPA approach with consideration of the influence of multiple neutron scattering enabled reliable decomposition of the SANS intensity distribution into the coherent and incoherent scattering components. To date, NPA has not been well established as a standard technique for SANS experiments at pulsed neutron sources such as the Japan Proton Accelerator Research Complex (J-PARC) and the US Spallation Neutron Source. It is anticipated that this work will contribute significantly to the accurate determination of the coherent neutron scattering component for scatterers in various types of organic sample systems in SANS experiments at J-PARC, particularly for systems involving competition between the coherent and incoherent scattering intensity.

Insight into neutron focusing: the out-of-focus condition

2013 ◽  
Vol 46 (5) ◽  
pp. 1361-1371 ◽  
Author(s):  
B. Hammouda ◽  
D. F. R. Mildner ◽  
A. Brûlet ◽  
S. Desert
Keyword(s):  
Standard Deviation ◽  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Neutron Wavelength ◽  
Focus Condition ◽  
The Mean ◽  
The Individual ◽  
Multiple Holes ◽  
Good Agreement

Neutron focusing leads to significant gains in flux-on-sample in small-angle neutron scattering and very small angle neutron scattering instruments. Understanding the out-of-focus condition is necessary for less than optimal conditions such as for short instruments and low neutron wavelengths. Neutron focusing is investigated using a three-pronged approach. The three methods are analytical calculations, resolution measurements and computer simulations. A source aperture containing a single small-size hole and a sample aperture containing multiple holes are used to produce multiple spots on the high-resolution neutron detector. Lens focusing elongates off-axis spots in the radial direction. The standard deviation for the size of each spot is estimated using these three approaches. Varying parameters include the neutron wavelength, the number of focusing lenses and the location of holes on the sample aperture. Enough agreement for the standard deviation of the individual neutron beams was found between the calculations and the measurements to give confidence in this approach. Good agreement was found between the standard deviations obtained from calculations and simulations as well. Excellent agreement was found for the mean location of these individual spots.

Toward a new lower limit for the minimum scattering vector on the very small angle neutron scattering spectrometer at Laboratoire Léon Brillouin

2008 ◽  
Vol 41 (1) ◽  
pp. 161-166 ◽  
Author(s):  
Annie Brûlet ◽  
Vincent Thévenot ◽  
Didier Lairez ◽  
Sébastien Lecommandoux ◽  
Willy Agut ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Pixel Size ◽  
Resolution Function ◽  
Incident Wavelength ◽  
Under Construction ◽  
Very High ◽  
Good Agreement ◽  
Small Pixel

The main characteristics of the very small angle neutron scattering spectrometer (VSANS) under construction at the Laboratoire Léon Brillouin are a multibeam pinhole collimator converging onto an image plate detector. By combining tiny collimation (diaphragms of around 1 or 2 mm in diameter) with the small pixel size of the detector (0.15 × 0.15 mm), very high resolution measurements can be achieved. The resolution function of the instrument contains a contribution from gravity, which is reduced by the intermediate masks of the collimator. Owing to the relatively short length of the VSANS instrument (around 14 m), this effect remains weak, in good agreement with the predictions. With a prototype multibeam collimator, an incident wavelength of 0.9 nm and the detector located at 6 m from the sample, it is possible to accessqvalues as low as 4 × 10−3 nm−1with very highqresolution. Promising preliminary experiments with highqresolution are reported, which open up new fields to the SANS technique.

Reduction and analysis of SANS and USANS data using IGOR Pro

2006 ◽  
Vol 39 (6) ◽  
pp. 895-900 ◽  
Author(s):  
Steven R. Kline
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Software Package ◽  
Small Angle Neutron Scattering ◽  
Data Sets ◽  
Graphical Interface ◽  
Model Independent ◽  
Analysis Models ◽  
Reduced Data ◽  
Modular Format

A software package is presented for performing reduction and analysis of small-angle neutron scattering (SANS) and ultra-small-angle neutron scattering (USANS) data. A graphical interface has been developed to visualize and quickly reduce raw SANS and USANS data into one- or two-dimensional formats for interpretation. The resulting reduced data can then be analyzed using model-independent methods or non-linear fitting to one of a large and growing catalog of included structural models. The different instrumental smearing effects for slit-smeared USANS and pinhole-smeared SANS data are handled automatically during analysis. In addition, any number of SANS and USANS data sets can be analyzed simultaneously. The reduction operations and analysis models are written in a modular format for extensibility, allowing users to contribute code and models for distribution to all users. The software package is based on Igor Pro, providing freely distributable and modifiable code that runs on Macintosh and Windows operating systems.

Neutron Scattering from a Ferrofluid

1994 ◽  
Vol 376 ◽  
Author(s):  
Min Y. Lin ◽  
Weili Luo ◽  
Jeffrey Lynn
Keyword(s):  
Magnetic Field ◽  
Electron Microscopy ◽  
Fractal Dimension ◽  
Neutron Scattering ◽  
Small Angle ◽  
Liquid State ◽  
Small Angle Neutron Scattering ◽  
Cluster Aggregation ◽  
High Concentrations ◽  
Average Size

ABSTRACTSmall angle neutron scattering experiments were performed on a eicosane-based ferrofluid. An average size of 88 Å can be extracted from the data, in agreement with results from electron microscopy. Below the frozen temperature of eicosane, however, the particles are seen to be in larger aggregates with a fractal dimension of 2.15, similar to those formed under reaction-limited cluster aggregation (RLCA) conditions. At high concentrations, particles form larger aggregates even in the liquid state. Applying a magnetic field introduces new structure and changes the density inside the aggregates.

scholarly journals Simulations of foil-based spin-echo (modulated) small-angle neutron scattering with a sample using McStas

2021 ◽  
Vol 54 (1) ◽  
pp. 195-202
Author(s):  
Wim G. Bouwman ◽  
Erik B. Knudsen ◽  
Linda Udby ◽  
Peter Willendrup
Keyword(s):  
Magnetic Field ◽  
Elastic Scattering ◽  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Spin Echo ◽  
Transmitted Beam ◽  
Further Development ◽  
Theory And Experiments ◽  
Good Agreement

For the further development of spin-echo techniques to label elastic scattering it is necessary to perform simulations of the Larmor precession of neutron spins in a magnetic field. The details of some of these techniques as implemented at the reactor in Delft are simulated. First, the workings of the magnetized foil flipper are simulated. A full virtual spin-echo small-angle neutron scattering instrument is built and tested without and with a realistic scattering sample. It is essential for these simulations to have a simulated sample that also describes the transmitted beam of unscattered neutrons, which usually is not implemented for the simulation of conventional small-angle neutron scattering (SANS) instruments. Finally, the workings of a spin-echo modulated small-angle neutron scattering (SEMSANS) instrument are simulated. The simulations are in good agreement with theory and experiments. This setup can be extended to include realistic magnetic field distributions to fully predict the features of future Larmor labelling elastic-scattering instruments. Configurations can now be simulated for more complicated combinations of SANS with SEMSANS.

Energy-resolved small-angle neutron scattering from steel

2017 ◽  
Vol 50 (2) ◽  
pp. 334-339 ◽  
Author(s):  
Yojiro Oba ◽  
Satoshi Morooka ◽  
Kazuki Ohishi ◽  
Jun-ichi Suzuki ◽  
Shin-ichi Takata ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Experimental Technique ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Recent Progress ◽  
Neutron Sources ◽  
Analysis Technique ◽  
Neutron Attenuation ◽  
Pulsed Neutron

Recent progress of pulsed neutron sources has enabled energy-resolved analysis of neutron attenuation spectra, which include information on neutron scattering. In this study, a new analysis technique for small-angle neutron scattering (SANS) is demonstrated. A clear difference is observed in the neutron attenuation spectra between steels with different nanostructures; this difference can be understood as arising from attenuation due to SANS. The neutron attenuation spectra calculated from the corresponding SANS profiles agree well with the experimentally observed attenuation spectra. This result indicates that measurement of neutron attenuation spectra may enable the development of a novel experimental technique,i.e.energy-resolved SANS.

The new high resolution ultra small-angle neutron scattering instrument at the High Flux Reactor in Grenoble

2000 ◽  
Vol 33 (3) ◽  
pp. 851-854 ◽  
Author(s):  
M. Hainbuchner ◽  
M. Villa ◽  
G. Kroupa ◽  
G. Bruckner ◽  
M. Baron ◽  
...  
Keyword(s):  
High Resolution ◽  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
High Flux ◽  
High Flux Reactor ◽  
Flux Reactor
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