Small-Angle neutron scattering facilities and polymer research at Oak Ridge

1986 ◽  
Vol 26 (10) ◽  
pp. 695-700 ◽  
Author(s):  
George D. Wignall
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Oak Ridge ◽  
Polymer Research

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.

Experimental Evidence of Super Densification of Adsorbed Hydrogen by in-situ Small Angle Neutron Scattering (SANS)

2011 ◽  
Vol 1334 ◽  
Author(s):  
Dipendu Saha ◽  
Lilin He ◽  
Cristian I. Contescu ◽  
Nidia C. Gallego ◽  
Yuri B. Melnichenko
Keyword(s):  
Neutron Scattering ◽  
Pore Size ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Hydrogen Gas ◽  
Necessary Condition ◽  
Adsorbed Hydrogen ◽  
Oak Ridge ◽  
Hydrogen Molecules

ABSTRACTEntrapping hydrogen molecules within the nanopores of solid adsorbents serves as a unique alternative for on-board storing of hydrogen for transportation purposes. The key advantage of the physisorption process for hydrogen storage is the higher density values achieved with the adsorbed gas, compared to that of the compressed phase, translating into higher storage capacities at lower pressures. The necessary condition for effective adsorption is the presence of narrow micropores of < 2 nm in width which provide the most suitable environment of hydrogen adsorption. Despite numerous theoretical calculations or indirect experimental estimations, there has not been a direct experimental measurement of the density of adsorbed hydrogen as a function of pressure and/or pore size. In the present study, we report on the use of in-situ small angle neutron scattering (SANS) to study the phase behavior of hydrogen confined in narrow micropores. We provide for the first time direct experimental measurements of the effect of pore size and pressure on hydrogen adsorbed on a polyfurfuryl alcohol-derived activated carbon (PFAC), at room temperature and pressures up to 207 bar. SANS studies were carried out at the General-Purpose Small-Angle Neutron Scattering spectrometer of the High Flux Isotope Reactor at Oak Ridge National Laboratory. The measurements covered the Q-range from 0.01 to 0.8 Å-1, covering the pores in the range of 9 to 34 Å of the PFAC material. Initial results suggest that the density of adsorbed hydrogen is higher than the density of bulk hydrogen gas and increases with decreasing pore size.

The Bio-SANS Small-Angle Neutron Scattering Instrument at Oak Ridge National Laboratory

Neutron News ◽  
2008 ◽  
Vol 19 (2) ◽  
pp. 22-23 ◽  
Author(s):  
William T. Heller ◽  
Gary W. Lynn ◽  
Volker S. Urban ◽  
Kevin Weiss ◽  
Dean A.A. Myles
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
National Laboratory ◽  
Oak Ridge ◽  
Oak Ridge National Laboratory

General Purpose Small-Angle Neutron Scattering Instrument on HFIR Oak Ridge

Neutron News ◽  
2008 ◽  
Vol 19 (3) ◽  
pp. 20-21 ◽  
Author(s):  
K.C. Littrell ◽  
K.M. Atchley ◽  
G. Cheng ◽  
Y.B. Melnichenko ◽  
G.D. Wignall
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
General Purpose ◽  
Oak Ridge

scholarly journals The extendedQ-range small-angle neutron scattering diffractometer at the SNS

2010 ◽  
Vol 43 (5) ◽  
pp. 1068-1077 ◽  
Author(s):  
J. K. Zhao ◽  
C. Y. Gao ◽  
D. Liu
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Neutron Transport ◽  
Signal To Noise Ratio ◽  
Counting Efficiency ◽  
Target Station ◽  
Oak Ridge ◽  
Wavelength Resolution ◽  
Neutron Momentum

The extendedQ-range small-angle neutron scattering diffractometer (EQ-SANS) at the Spallation Neutron Source (SNS), Oak Ridge, is designed for wide neutron momentum transfer (Q) coverage, high neutron beam intensity and good wavelength resolution. In addition, the design and construction of the instrument aim to achieve a maximum signal-to-noise ratio by minimizing the background. The instrument is located on the high-power target station at the SNS. One of the key components in the primary flight path is the neutron optics, consisting of a curved multichannel beam bender and sections of straight neutron guides. They are optimized to minimize neutron transport loss, thereby maximizing the available flux on the sample. They also enable the avoidance of a direct line of sight to the neutron moderator at downstream locations. The instrument has three bandwidth-limiting choppers. They allow a novel frame-skipping operation, which enables the EQ-SANS diffractometer to achieve a dynamicQrange equivalent to that of a similar machine on a 20 Hz source. The two-dimensional low-angle detector, based on3He tube technologies, offers very high counting rates and counting efficiency. Initial operations have shown that the instrument has achieved its design goals.

The 40 m general purpose small-angle neutron scattering instrument at Oak Ridge National Laboratory

2012 ◽  
Vol 45 (5) ◽  
pp. 990-998 ◽  
Author(s):  
George D. Wignall ◽  
Kenneth C. Littrell ◽  
William T. Heller ◽  
Yuri B. Melnichenko ◽  
Kathy M. Bailey ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
National Laboratory ◽  
Scattering Data ◽  
Large Area ◽  
High Count ◽  
Incident Wavelength ◽  
Oak Ridge ◽  
Oak Ridge National Laboratory

A series of upgrades have been undertaken at the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory, including the installation of a supercritical hydrogen moderator (T≃ 20 K), which has boosted the flux of long-wavelength neutrons by over two orders of magnitude. In order to take advantage of the new capabilities, a 40 m-long small-angle neutron scattering (SANS) instrument has been constructed, which utilizes a mechanical velocity selector, pinhole collimation and a high-count-rate (>105 Hz) large-area (1 m2) two-dimensional position-sensitive detector. The incident wavelength (λ), resolution (Δλ/λ), incident collimation and sample-to-detector distance are independently variable under computer control. The detector can be moved up to 45 cm off-axis to increase the overallQrange [<0.001 <Q= (4π/λ)sinθ < 1 Å−1, where 2θ is the angle of scatter]. The design and characteristics of this instrument are described, along with examples of scattering data to illustrate the performance.

First data acquired on the extendedQ-range small-angle neutron scattering (EQ-SANS) diffractometer at the Spallation Neutron Source

2011 ◽  
Vol 44 (5) ◽  
pp. 1120-1122 ◽  
Author(s):  
Dazhi Liu ◽  
Kunlun Hong ◽  
Carrie Y. Gao ◽  
Yuri Melnichenko ◽  
Ken Littrell ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Neutron Source ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
National Laboratory ◽  
Model Fitting ◽  
Scattering Data ◽  
Radius Of Gyration ◽  
Spallation Neutron Source ◽  
Oak Ridge

Initial experimental results are reported from the extendedQ-range small-angle neutron scattering (EQ-SANS) diffractometer at the Spallation Neutron Source at Oak Ridge National Laboratory (ORNL). A generation-8 polyamidoamine dendrimer was measured and the conformation parameters (radius of gyration, thickness of the soft shelletc.) extracted by model fitting to the scattering data. The results are compared with data collected at the general-purpose small-angle neutron scattering (GP-SANS) beamline at the High-Flux Isotopic Reactor at ORNL and show that EQ-SANS is ready for scientific studies for the small-angle neutron scattering community.

Absolute calibration of small-angle neutron scattering data

1987 ◽  
Vol 20 (1) ◽  
pp. 28-40 ◽  
Author(s):  
G. D. Wignall ◽  
F. S. Bates
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Scattering Data ◽  
Experimental Program ◽  
Absolute Calibration ◽  
Oak Ridge ◽  
Angle Scattering ◽  
Calibration Methods ◽  
Experimental Geometry

Absolute calibration forms a valuable diagnostic tool in small-angle neutron scattering (SANS) experiments, and allows the parameters of a given model to be restricted to the set which reproduces the observed intensity. Discrepancies between the observed and calculated intensities may arise from potential artifacts or even new physical processes and absolute calibration methods are useful in delineating these circumstances. General methods which are available for absolute scaling are discussed along with estimates of the degree of internal consistency which may be achieved between the various standards. In order to minimize the time devoted to calibration in a given experimental program, emphasis is placed on developing a set of precalibrated strongly scattering standards which may be run in the chosen experimental geometry. Comparison of such a set developed at the National Center for Small-Angle Scattering Research (Oak Ridge) with independent determinations by SANS users indicates consistency to within ± 5%.

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