ARCS White Beam Vanadium Normalization Data for SNS Cycle 2022B
Neutron scattering Data from a Vanadium cylinder. Acquired on the ARCS spectrometer in white beam mode to normalize the detector efficiencies. During Cycle 2022B
MATERIALS SCIENCE↗
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Results for “NEUTRON SCIENCE”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Time-Resolved Neutron Imaging for Hydrogen Uptake in Subsurface Lithologies
Contains the neutron radiography and tomography images of hydrogen uptake in different geological lithologies.
36 MATERIALS SCIENCE↗
Room temperature crystallography of human acetylcholinesterase bound to a substrate analogue 4K-TMA: Towards a neutron structure
Acetylcholinesterase (AChE) catalyzes hydrolysis of acetylcholine thereby terminating cholinergic nerve impulses for efficient neurotransmission. Human AChE (hAChE) is a target of nerve agent and pesticide organophosphorus compounds that covalently attach to the catalytic Ser203 residue. Reactivation of inhibited hAChE can be achieved with nucleophilic antidotes, such as oximes. Understanding structural and electrostatic (i.e. protonation states) determinants of the catalytic and reactivation processes is crucial to improve design of oxime reactivators. Here we report X-ray structures of hAChE conjugated with a reversible covalent inhibitor 4K-TMA (4K-TMA:hAChE) at 2.8 Å resolution and of 4K-TMA:hAChE conjugate with oxime reactivator methoxime, MMB4 (4K-TMA:hAChE:MMB4) at 2.6 Å resolution, both at physiologically relevant room temperature, as well as cryo-crystallographic structure of 4K-TMA:hAChE at 2.4 Å resolution. 4K-TMA acts as a substrate analogue reacting with the hydroxyl of Ser203 and generating a reversible tetrahedral hemiketal intermediate that closely resembles the first tetrahedral intermediate state during hAChE-catalyzed acetylcholine hydrolysis. Structural comparisons of room temperature with cryo-crystallographic structures of 4K-TMA:hAChE and published mAChE complexes with 4K-TMA, as well as the effect of MMB4 binding to the peripheral anionic site (PAS) of the 4K-TMA:hAChE complex, revealed only discrete, minor differences. The active center geometry of AChE, already highly evolved for the efficient catalysis, was thus indicative of only minor conformational adjustments to accommodate the tetrahedral intermediate in the hydrolysis of the neurotransmitter acetylcholine (ACh). To map protonation states in the hAChE active site gorge we collected 3.5 Å neutron diffraction data paving the way for obtaining higher resolution datasets that will be needed to determine locations of individual hydrogen atoms.
4K-TMA↗
Room-temperature neutron and X-ray data collection of 3CL M pro from SARS-CoV-2
The replication of SARS-CoV-2 produces two large polyproteins, pp1a and pp1ab, that are inactive until cleavage by the viral chymotrypsin-like cysteine protease enzyme (3CL M pro ) into a series of smaller functional proteins. At the heart of 3CL M pro is an unusual catalytic dyad formed by the side chains of His41 and Cys145 and a coordinated water molecule. The catalytic mechanism by which the enzyme operates is still unknown, as crucial information on the protonation states within the active site is unclear. To experimentally determine the protonation states of the catalytic site and of the other residues in the substrate-binding cavity, and to visualize the hydrogen-bonding networks throughout the enzyme, room-temperature neutron and X-ray data were collected from a large H/D-exchanged crystal of ligand-free (apo) 3CL M pro .
3CL Mpro↗
Magnon Dispersion in CeIn3
This dataset contains measurements of the low-energetic magnetic excitations in the heavy-fermion material CeIn3. Neutron spectroscopy data were recorded on a single-crystal mosaic of around 2 g total mass at the spectrometer CNCS. In a first row of measurements with incident neutron energy 12 meV the excitations were mapped out in major parts of the first Brillouin zone. In a second row of measurements with 3.315 meV incident neutron energy, the gapless and relatively steep dispersion in the vicinity of the R-point, corresponding to (1/2,1/2,1/2) in reciprocal space, was investigated.
excitations↗
An Easy‐to‐Use Custom‐Built Cell for Neutron Powder Diffraction Studies of Rechargeable Batteries
Abstract In operando powder diffraction remains one of the most powerful tools for non‐destructive investigation of battery electrode materials. While in operando X‐ray, especially synchrotron radiation, powder diffraction is by now a routine experimental technique, in operando neutron powder diffraction is still less established. We present a new electrochemical cell for in operando neutron powder diffraction, which is, first and foremost, easy to use, but can also cycle electrode materials under electrochemical conditions close to those achieved using standard laboratory cells. The cell has been designed in multiple sizes, and high‐quality electrochemical and neutron powder diffraction data is presented for sample sizes as low as 48 mg total active material. The cell handles lithium‐ion and sodium‐ion materials equally well, with no difference in how the cell is prepared and assembled. The cell is intended to be used as sample environment at powder diffractometers at the neutron facilities MLZ, ORNL and ACNS.
25 ENERGY STORAGE↗
Neutron crystallography for the study of hydrogen bonds in macromolecules
The hydrogen bond (H bond) is one of the most important interactions that form the foundation of secondary and tertiary protein structure. Beyond holding protein structures together, H bonds are also intimately involved in solvent coordination, ligand binding, and enzyme catalysis. The H bond by definition involves the light atom, H, and it is very difficult to study directly, especially with X-ray crystallographic techniques, due to the poor scattering power of H atoms. Neutron protein crystallography provides a powerful, complementary tool that can give unambiguous information to structural biologists on solvent organization and coordination, the electrostatics of ligand binding, the protonation states of amino acid side chains and catalytic water species. The method is complementary to X-ray crystallography and the dynamic data obtainable with NMR spectroscopy. Also, as it gives explicit H atom positions, it can be very valuable to computational chemistry where exact knowledge of protonation and solvent orientation can make a large difference in modeling. Finally, this article gives general information about neutron crystallography and shows specific examples of how the method has contributed to structural biology, structure-based drug design; and the understanding of fundamental questions of reaction mechanisms.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Grating-Based Imaging-Scattering with Portable Neutron Generator
Company: Adelphi Technology, Inc. Title: Grating-Based Imaging-Scattering with Portable Neutron Generator PI: Dr. Jay Theodore Cremer, Jr. Topic: 26a Statement of the problem or situation that is being addressed. Successful plant growth depends upon an efficient and robust root system. The plant root is part of a larger system of water and microbial flows in the soil system. While much effort has been exerted to develop an imaging system for water, microbes, and roots, the problem is challenging, and no widely accepted imaging method currently exists. The optical solutions use a highly modified soil system. X-ray imaging methods are insensitive to the soft tissues in the presence of sand. Thermal neutron imaging has been often tested, but found inadequate, due to limited access and low image resolution. This project will develop a new strategy for neutron imaging of plant/soil systems. The project will allow long duration experiments in greenhouse environments and increase the image information content to the micron scale. General statement of how this problem is being addressed. Portable, rugged thermal and fast neutron sources are being developed where portable means a two-soldier team can carry the source and power unit to survey rough terrain for explosives. In the past decade, microfabrication of X-ray and thermal/cold neutron optics has opened a new imaging strategy. The standard transmission image is now supplemented with simultaneous acquisition of a phase contrast image and an image revealing scattering features. In materials science, the interferometric neutron scattering image has been used to detect early crack formation in stressed additive manufacturing test samples. The detection requires sensitivity to scattering features at the 1-micron scale. By addition of our proposed grating-optic to Adelphi Technology’s radiographic/tomographic imaging system, which is based on portable thermal neutron source, the resulting thermal neutron scatter image of the plant/soil system, will reveal details at 1-micron. Commercial Applications and Other Benefits Neutron interferometry imaging has greater penetration through large metal components compared to industrial X-ray imaging. The low-cost, large area optics developed for greenhouse applications, combined with the robust, portable neutron generator, can then be marketed as a system for inspection of additive manufactured components. In the aerospace industry, all freshly printed components are validated with X-ray CT. Scheduled maintenance again requires X-ray CT as the ability to predict aerospace component lifetime does not yet exist. Large aerospace components are only partially observed with X-ray imaging. Key Words Neutron radiography/tomography, grating interferometry, thermal neutron generator imaging, plant root and soil imaging, rhizosphere imaging, deployable neutron imaging systems Summary for Members of Congress A rugged, portable source of thermal neutrons is adapted for neutron interferometry imaging with the addition of low-cost, 3D printed optics. The first application of our proposed deployable, compact thermal neutron generator imaging system, using a grating optic, is plant root/soil science in greenhouse settings and agricultural laboratories.
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
Ewald: an extended wide-angle Laue diffractometer for the second target station of the Spallation Neutron Source
Visualizing hydrogen atoms in biological materials is one of the biggest remaining challenges in biophysical analysis. While X-ray techniques have unrivaled capacity for high-throughput structure determination, neutron diffraction is uniquely sensitive to hydrogen atom positions in crystals of biological materials and can provide a more complete picture of the atomic and electronic structures of biological macromolecules. This information can be essential in providing predictive understanding and engineering control of key biological processes, for example, in catalysis, ligand binding and light harvesting, and to guide bioengineering of enzymes and drug design. One very common and large capability gap for all neutron atomic resolution single-crystal diffractometers is the weak flux of available neutron beams, which results in limited signal-to-noise ratios giving a requirement for sample volumes of at least 0.1 mm 3 . The ability to operate on crystals an order of magnitude smaller (0.01 mm 3 ) will open up new and more complex systems to studies with neutrons which will help in our understanding of enzyme mechanisms and enable us to improve drugs against multi resistant bacteria. With this is mind, an extended wide-angle Laue diffractometer, `Ewald', has been designed, which can collect data using crystal volumes below 0.01 mm 3 .
36 MATERIALS SCIENCE↗
Neutron Gamma Detector Systems for Planetary Science Applications
This documents a talk at the Arizona State University SESE engineering coffee. It describes neutron gamma detector systems.
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
INS spectra of NH3 and ND3 obtained at SEQUOIA spectrometer
These INS data were measured at SEQUOIA spectrometer. The samples used were NH3 and ND3, and empty container (background runs). The measurements were done with incident neutron energies Ei=30, 50, 85, 280 and 700 meV at T=5K, 50K, 100K, 180K, 200K for NH3 sample, and with Ei=30, 70, 200, 500 meV at T=5K, 50K, 100K, 180K, 200K and 230K for ND3.
excitations↗
Growth and characterization of uranium oxide thin films deposited by polymer assisted deposition
A thin film of uranium oxide was deposited by polymer assisted deposition on a single crystal lanthanum aluminate - strontium aluminum tantalate substrate. The deposition resulted in formation of epitaxial thin film of uranium oxide, which could be attributed to α-U 3 O 8 or α-UO 3 . X-ray diffraction revealed preferential orientation along (100) in case of α-U 3 O 8 or (001) for α-UO 3 for the thin film. A combination of x-ray and neutron reflectometry proved the sample to be α-U 3 O 8 . Furthermore, the film was of 17 nm thickness covered by a capping layer. The less dense capping layer could be a manifestation of surface water adsorbed on the sample.
36 MATERIALS SCIENCE↗
Identification of Material Type and Thickness Using Combined X-ray and Fast Neutron Radiography
Material identification (ID) using radiography is a problem that has implicitly existed since the discovery of the X-ray. Since 9-11, this problem has received renewed attention for homeland security applications of the generic, “what is in the box?” type1. Examples of items potentially in the box include: roadside bombs, nuclear weapons, contraband shipments and the like. In these cases, the “what” can include: explosives, projectiles, fissile material, or drugs. Here we investigate the ability of 60Co gamma-rays, 14MeV neutrons, and their combination to tease apart information about density, thickness and atomic number of items in the box. That information subset can be combined with other types of independent information (e.g. neutron and gammaspectroscopy, intelligence, photographs etc.) to assert a more complete picture of what, exactly, is in the box? That more complete information set can form the basis for actions including: remote detonation, evacuations, disablement, detention, search, arrest etc.
36 MATERIALS SCIENCE↗
Post Irradiation Examination of Fast Neutron Irradiated 14YWT Tubes at Nuclear Science User Facilities
Cladding materials for next generation nuclear reactors require resistance to high doses of fast neutron flux. Work through the Department of Energy's (DOE) Nuclear Technology Research and Development (NTR and D) Program's Advanced Fuel Campaign has identified 14YWT, a nano-ferritic oxide dispersion strengthened alloy as a promising alloy and has made a 50 kg batch of material, FCRD-NFA1, with nominal composition Fe-14Cr-3W0.4Ti-0.2Y in weight percentage. Plates were extruded from milled powder at Oak Ridge National Laboratory and then electro-discharge machined (EDM) into two sizes of tubes at Los Alamos National Laboratory (LANL). The OD of the tubes were polished to remove the EDM recast layer. Twenty-four of these tubes were placed into the BOR60 reactor, a sodium fast reactor, at the RIAR lab in Dimitrovgrad Russia. Irradiation conditions depended on exact location within the reactor, but the two samples in this study (L108 and L202) were irradiated to 7 dpa at 360-370 deg. C (Sample L108), and 6 dpa at 385-430 deg. C (L202). More detailed temperature models are pending for sample L202. Post irradiation examination took place at both LANL and the University of California, Berkeley (UCB). Facilities used at LANL (CMR Wing 9 Hot Cells, Electron Microscopy Lab (EML)) are part of a pending NSUF partner facility application, while the work at UCB was completed under a Nuclear Science User Facility, Rapid Turnaround Experiment Proposal (NSUF-RTE)
36 MATERIALS SCIENCE↗
Restart of the Transient Reactor Test (TREAT) Facility Neutron Radiography Program
The TREAT radiography system is used to perform neutron radiography of fuels, experiments, and other specimens before and after irradiation within the TREAT reactor. The TREAT neutron radiography facility performed approximately 5,000 radiographs by the spring of 1977. Originally built in 1958, the TREAT Facility was in operation until it was placed in a shutdown status in 1994. Following the Fukishima disaster and seeing a need for enhanced accident tolerant fuels, the United Stated Department of Energy decided to restart the TREAT facility and resume transient operations. In November 2017, the TREAT reactor was successfully restarted and is currently performing operational testing in preparation for initial experiment irradiations and transient testing. This paper discusses efforts to reactivate the TREAT neutron radiography facility. To characterize the neutron beam, gold foil activation measurements were made to determine an average neutron flux and flux profile. An open beam image provides the information about variations in the beam profile. In conclusion, a series of system qualification radiographs have been acquired to determine the effective image acquisition parameters, resulting image quality, and the relationships between the two.
36 MATERIALS SCIENCE↗
Study on the residual stress relaxation in girth-welded steel pipes under bending load using diffraction methods
This research is dedicated to the experimental investigation of the residual stress relaxation in girth-welded pipes due to quasi-static bending loads. Ferritic-pearlitic steel pipes are welded with two passes, resulting in a characteristic residual stress state with high tensile residual stresses at the weld root. Also, four-point bending is applied to generate axial load stress causing changes in the residual stress state. These are determined both on the outer and inner surfaces of the pipes, as well as in the pipe wall, using X-ray and neutron diffraction. Focusing on the effect of tensile load stress, it is revealed that not only the tensile residual stresses are reduced due to exceeding the yield stress, but also the compressive residual stresses for equilibrium reasons. Furthermore, residual stress relaxation occurs both parallel and perpendicular to the applied load stress.
36 MATERIALS SCIENCE↗
Study of Protein Dynamics via Neutron Spin Echo Spectroscopy
Most human body proteins' activity and functionality are related to configurational changes of entire subdomains within the protein crystal structure. The crystal structures build the basis for any calculation that describes the structure or dynamics of a protein, most of the time with strong geometrical restrictions. However, these restrictions from the crystal structure are not present in the solution. The structure of the proteins in the solution may differ from the crystal due to rearrangements of loops or subdomains on the pico to nanosecond time scale (i.e., the internal protein dynamics time regime). This study describes how slow motions on timescales of several tens of nanoseconds can be accessed using neutron scattering. In particular, the dynamical characterization of two major human proteins, an intrinsically disordered protein that lacks a well-defined secondary structure and a classical antibody protein, is addressed by neutron spin echo spectroscopy (NSE) combined with a wide range of laboratory characterization methods. Further insights into protein domain dynamics were achieved using mathematical modeling to describe the experimental neutron data and determine the crossover between combined diffusive and internal protein motions. The extraction of the internal dynamic contribution to the intermediate scattering function obtained from NSE, including the timescale of the various movements, allows further vision into the mechanical properties of single proteins and the softness of proteins in their nearly natural environment in the crowded protein solution.
59 BASIC BIOLOGICAL SCIENCES↗
Particle Energy Spectrum, Revisited from a Counting Statistics Perspective
In nuclear science, gamma and neutron spectra are counted energy by energy, and then particle by particle. Until recently, few studies have been performed on how exactly those energy spectra are counted, or how those counts are correlated. Because of lack of investigation, cross section covariance and correlation matrices are usually estimated using perturbation method. We will discuss a statistical counting scheme that shall mimic the gamma and neutron counting process used in nuclear science. From this counting scheme, the cross section covariance and correlation can be statistically derived.
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗