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.

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

Study of a multi-pinhole collimation system based small-angle neutron scattering instrument at the Compact Pulsed Hadron Source

2018 ◽  
Vol 51 (6) ◽  
pp. 1605-1615
Author(s):  
Zhiyuan Wang ◽  
Huarui Wu ◽  
Liang Chen ◽  
Liangwei Sun ◽  
Xuewu Wang
Keyword(s):  
Neutron Scattering ◽  
Sample Size ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Signal To Noise Ratio ◽  
Safety Margin ◽  
Beam Intensity ◽  
Opening Angle ◽  
Collimation System ◽  
Sans Instrument

The neutron flux of the Compact Pulsed Hadron Source (CPHS) is about 2–3 orders of magnitude lower than that of large neutron sources, which means that the beam intensity should be improved to achieve good statistics. Multi-pinhole collimation can be used to obtain a lower Q with an acceptable beam intensity in a very small angle neutron scattering (VSANS) instrument and a higher beam intensity for a larger sample size in a small-angle neutron scattering (SANS) instrument. A new nine-pinhole structure is used in a SANS instrument at CPHS to achieve an acceptable range and resolution of Q and a higher beam intensity compared to single-pinhole collimation. The crosstalk issue associated with multi-pinhole collimation is addressed using an optimized algorithm to achieve a higher safety margin and a larger pinhole size with a higher beam intensity at the sample. Different collimator aperture structures are compared on the basis of their noise production. Experiments are performed to verify the theory of calculating reflection noise from the inner surface of the collimator's aperture and parasitic noise from the beveled collimator structure. From a simulated SANS experiment using cold neutrons in the SANS instrument, it is clarified that multi-pinhole collimators with an opening angle on the downstream side have better performance than those with an opening angle on the upstream side and straight-cut collimators. Compared with a single-pinhole collimation system, a nine-pinhole collimation system increases the intensity at the sample by approximately sevenfold when the sample size is increased by 20-fold for CPHS-SANS, and the signal-to-noise ratio is improved by exploiting a specific collimator aperture structure. Our goal is to install a multi-pinhole collimator based SANS instrument at CPHS in the future, and it is hoped that these results will serve to promote the utilization of multi-pinhole collimation systems at other facilities.

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 Tuning the instrument resolution using chopper and time of flight at the small-angle neutron scattering diffractometer KWS-2

2015 ◽  
Vol 48 (6) ◽  
pp. 1849-1859 ◽  
Author(s):  
Aurel Radulescu ◽  
Noémi Kinga Székely ◽  
Stephan Polachowski ◽  
Marko Leyendecker ◽  
Matthias Amann ◽  
...  
Keyword(s):  
Data Acquisition ◽  
Neutron Scattering ◽  
Small Angle ◽  
High Intensity ◽  
Small Angle Neutron Scattering ◽  
Time Of Flight ◽  
Standard Samples ◽  
Experimental Resolution ◽  
Wavelength Resolution ◽  
At Will

Following demand from the user community regarding the possibility of improving the experimental resolution, the dedicated high-intensity/extendedQ-range SANS diffractometer KWS-2 of the Jülich Centre for Neutron Science at the Heinz Maier-Leibnitz Center in Garching was equipped with a double-disc chopper with a variable opening slit window and time-of-flight (TOF) data acquisition option. The chopper used in concert with a dedicated high-intensity velocity selector enables the tuning at will of the wavelength resolution Δλ/λ within a broad range, from 20% (standard) down to 2%, in a convenient and safe manner following pre-planned or spontaneous decisions during the experiment. The new working mode is described in detail, and its efficiency is demonstrated on several standard samples with known properties and on a completely new crystallizable copolymer system, which were investigated using both the conventional (static) and TOF modes.

Study on Calibrating Neutron Velocity Selector of Small Angle Neutron Scattering Instrument

2013 ◽  
Vol 433-435 ◽  
pp. 837-843
Author(s):  
Zhou Xiang Yu ◽  
Yun Tao Liu ◽  
He Cheng ◽  
Li Zhang ◽  
Dong Feng Chen
Keyword(s):  
Measurement Error ◽  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Dead Time ◽  
Resolution Rate ◽  
Upper Limits ◽  
Wavelength Resolution ◽  
Total Measurement Time ◽  
First Time

Neutron velocity selector is widely used on neutron scattering instruments as key component. To calibrate it (wavelength and wavelength-resolution-rate measurement), it is necessary to design calibration instrument and develop calibration technique. Based on small angle neutron scattering instrument (SANS) at China Advanced Research Reactor (CARR), instrument structure was designed and instrument parameters were determined. Count loss influence on measurement of wavelength resolution rate (WRR) was studied for the first time. Measurement error of WRR is decided by product of dead time and Gauss peak count rate (GPCR) and increases with increasing GPCR for the same dead time. In order to ensure WRR measurement error less than 0.9%, upper limits of GPCR for detector adjoining chopper and detector far away from chopper are less than 10000[s-1] and 2500[s-1] respectively. According to upper limits of GPCR, floor limit of total measurement time for each spectrum is calculated to be 6.66 minutes.

Performance and characteristics of the BILBY time-of-flight small-angle neutron scattering instrument

2019 ◽  
Vol 52 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Anna Sokolova ◽  
Andrew E. Whitten ◽  
Liliana de Campo ◽  
Jason Christoforidis ◽  
Andrew Eltobaji ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Materials Science ◽  
Time Of Flight ◽  
Nuclear Science ◽  
Scientific Disciplines ◽  
Wide Range ◽  
Wavelength Resolution ◽  
Reference Samples

BILBY is a recently constructed and commissioned time-of-flight small-angle neutron scattering instrument, operated by the Australian Centre for Neutron Scattering at the Australian Nuclear Science and Technology Organisation (ANSTO). BILBY provides a wide accessible q range (q ≃ 1.0 × 10−3 Å−1 to ∼1.8 Å−1) and variable wavelength resolution (Δλ/λ ≃ 3–30%) to complement the other small-angle and ultra-small-angle neutron scattering capabilities available at ANSTO. Since its construction, BILBY has been used to study samples from a wide range of scientific disciplines, including biology, chemistry, physics and materials science. This article describes the BILBY design and components, and shows data collected from a number of reference samples.

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