WG2 Summary: Small-x, Diffraction and Vector Mesons
Here we briefly summarize the contributions to Working Group 2: Small-x, Diffraction and Vector Mesons, at the DIS2021 Workshop.
Altinoluk, Tolga↗
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Ultra-low Emittance Photocathodes for Accelerators and Femtosecond Electron Diffraction
To advance low emittance photocathodes suitable for accelerators and ultrafast electron diffraction the following directions have been investigated: 1) growth and characterization of alkali photocathodes in the new regime where their intrinsic emittance is limited by the material lattice temperature; 2) extending Monte Carlo electron transport modeling in photocathodes to cryogenic temperatures; 3) numerical simulations of sharp photo-emitting tips that enhance the electric field available; and 4) exploration of new protective coatings on III-V semiconductor photocathodes as robust high efficiency low-emittance sources of electrons. The key results achieved in these four areas as enabled by this grant are highlighted in this final technical report.
42 ENGINEERING↗
Understanding the U 3 Si 2 crystal structure evolution as a function of temperature by neutron diffraction and simulation
U 3 Si 2 is actively researched as an accident tolerant fuel. Detailed knowledge of the crystal structure evolution, including knowledge of the anisotropic tetragonal lattice parameters, as a function of temperature and chemical composition is of paramount importance for predictions ranging from thermo-mechanical stresses to phase transformations to crystal lattice sites of fission products. Knowledge of the stability range of U 3 Si 2 is of great importance to understand whether changes of the stoichiometry, either from burn-up or due to synthesis variations, will lead to undesirable phase decomposition. To investigate these topics, stoichiometric U3Si2.00 and hyper-stoichiometric U 3 Si 2.01 were synthesized and characterized at ambient conditions and up to 1150°C using time-of-flight neutron diffraction on the HIPPO instrument at the Los Alamos Neutron Science Center (LANSCE) at LANL.
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
Developing inductively driven diagnostic X-ray sources to enable transformative radiography and diffraction capabilities on Z
Penetrating X-rays are one of the most effective tools for diagnosing high energy density experiments, whether through radiographic imaging or X-ray diffraction. To expand the X-ray diagnostic capabilities at the 26-MA Z Pulsed Power Facility, we have developed a new diagnostic X-ray source called the inductively driven X-pinch (IDXP). This X-ray source is powered by a miniature transmission line that is inductively coupled to fringe magnetic fields in the final power feed. The transmission line redirects a small amount of Zs magnetic energy into a secondary cavity where 150+ kA of current is delivered to a hybrid X-pinch. In this report, we describe the multi-stage development of the IDXP concept through experiments both on Z and in a surrogate setup on the 1 MA Mykonos facility. Initial short-circuit experiments to verify power ow on Z are followed by short-circuit and X-ray source development experiments on Mykonos. The creation of a radiography-quality X-pinch hot spot is verified through a combination of X-ray diode traces, laser shadowgraphy, and source radiography. The success of the IDXP experiments on Mykonos has resulted in the design and fabrication of an IDXP for an upcoming Z experiment that will be the first-ever X-pinch fielded on Z. We have also pursued the development of two additional technologies. First, the extended convolute post (XCP) has been developed as an alternate method for powering diagnostic X-pinches on Z. This concept, which directly couples the current owing in one of the twelve Z convolute posts to an X-pinch, greatly increases the amount of available current relative to an IDXP (900 kA versus 150 kA). Initial short-circuit XCP experiments have demonstrated the efficacy of power ow in this geometry. The second technology pursued here is the inductively driven transmission line (IDTL) current monitor. These low-current IDTLs seek to measure the current in the final power feed with high fidelity. After three generations of development, IDTL current monitors frequently return cleaner current measurements than the standard B-dot sensors that are fielded on Z. This is especially true on high-inductance experiments where the harshest conditions are created in the nal power feed.
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
A Platform-Independent X-ray Diffraction Diagnostic for Phase Transition Kinetics in Traditional and Synthetic Microstructure Materials (LDRD Project 213088 Final Report)
Pulsed-power generators using the magnetic loading technique are able to produce well-controlled continuous ramp compression of condensed matter for high-pressure equation-of-state studies. X-ray diffraction (XRD) data from dynamically compressed samples provide direct measurements of the elastic compression of the crystal lattice, onset of plastic flow, strength-strain rate dependence, structural phase transitions, and density of crystal defects such as dislocations. Here, we present a cost effective, compact X-ray source for XRD measurements on pulsed-power-driven ramp-loaded samples. This combination of magnetically-driven ramp compression of materials with single, short-pulse XRD diagnostic will be a powerful capability for the dynamic materials community. The success in fielding this new XRD diagnostic dramatically improves our predictive capability and understanding of rate-dependent behavior at or near phase transition. As Sandia plans the next-generation pulse-power driver platform, a key element needed to deliver new state-of-the-art experiments will be having the necessary diagnostic tools to probe new regimes and phenomena. These diagnostics need to be as versatile, compact, and portable as they are powerful. The development of a platform-independent XRD diagnostic gives Sandia researchers a new window to study the microstructure and phase dynamics of materials under load. This project has paved the way for phase transition research in a variety of materials with mission interest.
36 MATERIALS SCIENCE↗
X-ray diffraction and scanning electron microscope characterizations of the salt waste processing facility tank 101 and tank 104 solid samples
The “as-received” Salt Waste Processing Facility (SWPF) Tank 101 and two Tank 104 samples (pre-wash and washed solids) have been characterized using x-ray diffraction (XRD) and scanning electron microscope/energy dispersive x-ray (SEM/EDX) techniques to address the concerns for the existence of solids, which may interfere with the operational performance of the SWPF crossflow filtration process.
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
Estimation of single crystal elastic constants in low symmetry materials using neutron diffraction
The use of constrained global optimization appears to be a potential way to estimate single crystal elastic constants for low symmetry materials from diffraction measurements
36 MATERIALS SCIENCE↗
Diffractive Multiplexing for High-Throughput Roll-to-Roll Laser Patterning of Flexible Organic Photovoltaic Modules (Final Report)
The purpose of this project is to demonstrate a cost-effective, high-throughput roll-to-roll (R2R) process for patterning of flexible, semitransparent organic photovoltaic (OPV) modules by developing diffractive optics-based laser multiplexing (DOL Multiplexing). DOL Multiplexing allows a single, high-powered laser source to perform parallel scribing across the R2R web width in a manner compatible with high process speeds. Such a process could have enormous benefits in terms of increased process speeds and reduced costs, both up-front capital costs, and long-term operational costs, over galvanometer-based step and scan methods or many-laser systems.
14 SOLAR ENERGY↗
Two-beam Bragg diffraction, filtering, and delays
We summarize transmission and reflection amplitudes of Bragg-crystals based on two-beam Bragg diffraction theory. Then, we consider a specific case of infinitely thick and symmetrical Bragg-crystal and its reflective properties in spectral and angular domain. We obtain analytical expressions for filtering width and respective delay amplitudes, temporal delay from spectral phase shift and spatial displacement from angular phase shift.
43 PARTICLE ACCELERATORS↗
Time-resolved Flash X-ray Diffraction of Aluminized High Explosives [Slides]
Al HE generally has lower performance in Detonation Driving Zone but higher overall blast effects than non-aluminized HE. Objective is to develop benchtop system for dynamic x-ray diffraction (XRD) of aluminized HE.
45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗
New dynamic diamond anvil cell for time-resolved radial x-ray diffraction
The dynamic diamond anvil cell (dDAC) is a recently developed experimental platform that has shown promise for studying the behavior of materials at strain rates ranging from intermediate to quasi-static and shock compression regimes. Combining dDAC with time-resolved x-ray diffraction (XRD) in the radial geometry (i.e., with incident x-rays perpendicular to the axis of compression) enables the study of material properties such as strength, texture evolution, and deformation mechanisms. This work describes a radial XRD dDAC setup at beamline P02.2 (Extreme Conditions Beamline) at DESY’s PETRA III synchrotron. Time-resolved radial XRD data are collected for titanium, zirconium, and zircon samples, demonstrating the ability to study the strength and texture of materials at compression rates above 300 GPa/s. In addition, the simultaneous optical imaging of the DAC sample chamber is demonstrated. The ability to conduct simultaneous radial XRD and optical imaging provides the opportunity to characterize plastic strain and deviatoric strain rates in the DAC at intermediate rates, exploring the strength and deformation mechanisms of materials in this regime.
47 OTHER INSTRUMENTATION↗
X-Ray Generation for Diffraction Experiments on Z
Explanation of the concept and benefit of X-ray diffraction in the context of material sciences on Z. Explanation why we use ZBL and ZPW for these experiments and what the progress on X-ray generation for this purpose is.
Geissel, Matthias↗
The Measurement of Grain Size by Electron Beam Backscattered Diffraction
The method of electron back-scatter diffraction provides an analytic means to identify crystalline phase and the grain size of structural materials. The need to utilize imaging parameters consistent with revealing the contributing microstructural scale is often overlooked through packaged imaging scripts. It is shown that imaging parameters consistent with a post processing assessment of low misorientation angles between boundaries are achievable as using pixel sizes on the order of 10 1 nm.
36 MATERIALS SCIENCE↗
Neutron Diffraction Residual Stress Characterization of Large-Scale Components by WA-DED
Two large scale 316L stainless steel cylindrical shells were fabricated by wire arc directed energy deposition (WA DED). Residual stresses were measured by neutron diffraction, and the microstructure and mechanical properties of the printed material were characterized. Longitudinal and transverse residual stresses were compressive at the inner diameter, near neutral at mid wall, and tensile at the outer diameter; radial (through thickness) residual stresses were relatively low in magnitude, and peak tensile residual stresses occurred at the outer diameter surface along the longitudinal direction. The printed 316L SS exhibited a heterogeneous microstructure with finely dispersed δ ferrite, and demonstrated high yield and tensile strengths with large elongation and ductile fracture at ambient temperature and at 250 °C. These results indicate that the outer diameter surface and near surface regions—where tensile residual stress is highest—are the most vulnerable to residual stress–sensitive failure modes, such as stress corrosion cracking and fatigue.
36 MATERIALS SCIENCE↗
Residual Strains in an Additively Processed Ni-based Superalloy Transpiration-Cooled Aerodynamic Leading Edge Structure using Neutron Diffraction
Selective Laser Melting (SLM) is a well-known additive manufacturing method based on a layer-by-layer building process that is capable of fabricating gas turbine Ni-based superalloy parts with complex and integrated cooling geometries that are typically not achievable using conventional casting methods. However, the impact of residual stress concentration on SLM component life is a concern. In this work, residual strains present at room temperature in an SLM Inconel 718 generic aerodynamic leading edge segment with transpiration cooling were investigated using neutron diffraction at Oak Ridge National Laboratory. This study reveals that areas of the part where complex cooling holes were printed exhibit residual tensile strains that can be detrimental to its integrity. The study paves the way for future studies of the design of cooling hole geometries and manufacturing parameters that achieve improved cooling while minimizing stress concentration effects.
Fouliard, Quentin↗
Synchrotron Microbeam Diffraction Studies on the Alignment within 3D-Printed Smectic-A Liquid Crystal Elastomer Filaments during Extrusion
3D printing of novel and smart materials has received considerable attention due to its applications within biological and medical fields, mostly as they can be used to print complex architectures and particular designs. However, the internal structure during 3D printing can be problematic to resolve. We present here how time-resolved synchrotron microbeam Small-Angle X-ray Diffraction (μ-SAXD) allows us to elucidate the local orientational structure of a liquid crystal elastomer-based printed scaffold. Most reported 3D-printed liquid crystal elastomers are mainly nematic; here, we present a Smectic-A 3D-printed liquid crystal elastomer that has previously been reported to promote cell proliferation and alignment. The data obtained on the 3D-printed filaments will provide insights into the internal structure of the liquid crystal elastomer for the future fabrication of liquid crystal elastomers as responsive and anisotropic 3D cell scaffolds.
36 MATERIALS SCIENCE↗
Selection of CVD Diamond Crystals for X-ray Monochromator Applications Using X-ray Diffraction Imaging
A set of 20 single crystal diamond plates synthesized using chemical vapor deposition (CVD) was studied using X-ray diffraction imaging to determine their applicability as side-bounce (single-reflection) Laue monochromators for synchrotron radiation. The crystal plates were of optical grade (as provided by the supplier) with (001) nominal surface orientation. High dislocation density was found for all samples. Distortions in the crystal lattice were quantified for low-index Laue reflections of interests using rocking curve topography. Maps of effective radius of curvature in the scattering plane were calculated using spline interpolation of the rocking curve peak position across the studied plates. For several selected plates, nearly flat regions with large effective radius of curvature were found (R 0 ≳ 30 - 70 m, some regions as large as 1 × 4 mm 2 ). The average width of the rocking curve for these regions was found to be about 150 μ rad (r.m.s.). These observations suggest that the selected CVD diamond plates could be used as intermediate-bandwidth monochromators refocusing the radiation source to a specific location downstream with close to 1:1 distance ratio.
36 MATERIALS SCIENCE↗
A Quantitative Phase Analysis by Neutron Diffraction of Conventional and Advanced Aluminum Alloys Thermally Conditioned for Elevated-Temperature Applications
As the issue of climate change becomes more prevalent, engineers have focused on developing lightweight Al alloys capable of increasing the power density of powertrains. The characterization of these alloys has been focused on mechanical properties and less on the fundamental response of microstructures to achieve these properties. Therefore, this study assesses the quality of the microstructure of two high-temperature Al alloys (A356 + 3.5RE and Al-8Ce-10Mg), comparing them to T6 A356. These alloys underwent thermal conditioning at 250 and 300 °C for 200 h. Time-of-flight neutron diffraction experiments were performed before and after conditioning. The phase evolution was quantified using Rietveld refinement. It was found that the Si phase grows significantly (13–24%) in T6 A356, A356 + 3.5RE, and T6 A356 + 3.5RE alloys, which is typically correlated with a reduction in mechanical properties. Subjecting the A356 3.5RE alloy to a T6 heat treatment stabilizes the orthorhombic Al4Ce3Si6 and monoclinic β-Al5FeSi phases, making them resistant to thermal conditioning. These two phases are known for enhancing mechanical properties. Additionally, the T6 treatment reduced the vol.% of the cubic Al20CeTi2 and hexagonal ᴨ-Al9FeSi3Mg5 phases by 13% and 23%, respectively. These phases have detrimental mechanical properties. The Al-8Ce-10Mg alloy cubic β-Al3Mg2 phase showed significant growth (82–101%) in response to conditioning, while the orthorhombic Al11Ce3 phase remained stable. The growth of the beta phase is known to decrease the mechanical properties of this alloy. These efforts give valuable insight into how these alloys will perform and evolve in demanding high-temperature environments.
Chemistry↗