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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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At least 757 records · Page 42
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Exceptional hardness in multiprincipal element alloys via hierarchical oxygen heterogeneities

Refractory multiprincipal element alloys (RMPEAs) are potential successors to incumbent high-temperature structural alloys, although efforts to improve oxidation resistance with large additions of passivating elements have led to embrittlement. RMPEAs containing group IV and V elements have a balance of properties including moderate ductility, low density, and the necessary formability. We find that oxidation of group IV-V RMPEAs induces hierarchical heterogeneities, ranging from nanoscale interstitial complexes to tertiary phases. This microstructural hierarchy considerably enhances hardness without indentation cracking, with values ranging between 12.1 and 22.6 GPa from the oxide-adjacent metal to the surface oxides, a 3.7 to 6.8× increase over the interstitial-free alloy. Our fundamental understanding of the oxygen influence on phase formation informs future alloy design to enhance oxidation resistance and obtain exceptional hardness while preserving plasticity.

Science & Technology - Other Topics↗
DOE OSTI2013

Nitrogen soft and hard X-ray emissions using different shapes of anodes in a 4-kJ plasma focus device

The effect of different anode tip geometries on the intensity of soft and hard X-rays emitted from a 4-kJ plasma focus device is investigated using five different anode tips. The shapes of the uppermost region of these anodes (tips) have been cylindrical-flat, cylindrical-hollow, spherical-convex, cone-flat, and cone-hollow. For time-resolved measurement of the emitted X-rays, several BPX-65 pin diodes covered by different filters and a fast plastic scintillator are used. Experimental results have shown that, the highest intensity of the both soft and hard X-ray is recorded in cone-flat, spherical-convex, and cone-hollow tips, respectively. The use of cone-flat anode tip has augmented the emitted X-ray three times.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2018

Changes in the Structure and Mechanical Properties of Hard Elastic and Porous Polypropylene Films upon Annealing and Orientation

The effect of the annealing temperature on the characteristics of hard elastic polypropylene samples obtained by annealing of extruded films and having an oriented lamellar structure is studied. It is established using the methods of X-ray scattering and differential scanning calorimetry that the lamellae thickness, the large period, and the degree of orientation of the folded lamellae increase with an increase in the annealing temperature, which is accompanied by an increase in the melting temperature and enthalpy. Porous films are obtained by uniaxial extension of the annealed samples in the orientation direction. It is shown that the porosity and permeability of the porous films increase with an increase in the annealing temperature, owing to an increase in the number and sizes of the through channels. The mechanical characteristics (strength, elastic modulus, and break elongation) of the hard elastic and porous films are measured, and their relationship with changes in the structure and orientation of the samples, depending on the annealing temperature, is established.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2016

Aperiodic Mo/Si multilayers for hard x-rays

In this work we have developed aperiodic Molybdenum/Silicon (Mo/Si) multilayers (MLs) to reflect 16.25 keV photons at a grazing angle of incidence of 0.6° ± 0.05°. To the best of our knowledge this is the first time this material system has been used to fabricate aperiodic MLs for hard x-rays. At these energies new hurdles arise. First of all a large number of bilayers is required to reach saturation. This poses a challenge from the manufacturing point of view, as thickness control of each ML period becomes paramount. The latter is not well defined a priori, due to the thickness of the interfacial silicide layers which has been observed to vary as a function of Mo and Si thickness. Additionally an amorphous-to-crystalline transition for Mo must be avoided in order maintain reasonably low roughness at the interfaces. This transition is well within the range of thicknesses pertinent to this study. Despite these difficulties our data demonstrates that we achieved reasonably flat ML response across the angular acceptance of ± 0.05°, with an experimentally confirmed average reflectivity of 28%. Such a ML prescription is well suited for applications in the field of hard x-ray imaging of highly diverging sources.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Optics-on-a-chip for ultrafast manipulation of 350-MHz hard x-ray pulses

Microelectromechanical systems (MEMS) are miniature devices integrated into a vast range of industrial and consumer applications. Optical MEMS are developed for dynamic spatiotemporal control in lightwave manipulation and communication as modulators, switches, multiplexers, spectrometer, etc. However, they have not been shown to function similarly in sub-nm wavelength regimes, namely, with hard x-rays, as high-brilliance pulsed x-rays have proven powerful for addressing challenges in time-domain science, from energy conversion to neurobiological control. While desirable temporal properties of x-ray pulses can be enhanced by optics, conventional x-ray optics are inherently massive in size, hence, never dynamic. We demonstrate highly ultrafast x-ray optics-on-a-chip based on MEMS capable of modulating hard x-ray pulses exceeding 350 MHz, 10 3 × higher than any other mechanical modulator, with a pulse purity >10 6 without compromising the spectral brilliance. Moreover, the timing characteristics of the devices can be tuned on-the-fly to deliver optimal pulse properties to create a host of dynamic x-ray instruments and applications, impossible with traditional optics of 10 9 × bulkier and more massive. The advent of the ultrafast optics-on-a-chip heralds a new paradigm of x-ray photonics, time-domain science, and accelerator diagnostics, especially at not only the future-generation light sources that offer coherent and high-frequency pulses but also lab-based facilities that normally do not offer timing structures.

42 ENGINEERING↗
DOE OSTI2022

Characterization of a hard X-ray self-seeding diamond crystal orientation

We present a method to accurately control the photon energies for hard X-ray Self-seeding schemes with a single crystal monochromator in transmissive geometry. The energy calibration is performed by measuring which pairs of the machine pitch and yaw angles for different crystallographic planes reflect the X-ray at the same wavelength. The free parameters of an analytical formula for the self-seeding energies are determined by fitting the observed intersections and the normalized derivative with respect to the pitch and yaw angles in the observed intersections. The method requires a hard X-ray spectrometer, but it does not rely on its absolute energy calibration. Instead, identifying the self-seeded energies above the SASE background or the monochromatic notches within the SASE bandwidth is sufficient for the calibration.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2026

Few-femtosecond time resolution in optically pumped hard X-ray scattering at a free-electron laser

Capturing chemical dynamics in real time is a central goal of ultrafast science, necessitating measurements fast enough to track atomic motion on few-femtosecond timescales with high precision. We present time-resolved hard X-ray scattering that meets these criteria by combining 7 fs full-width at half maximum (FWHM) near-infrared laser pulses with sub10 fs FWHM hard X-ray pulses from a free-electron laser. Using heavy water’s electronic response to strong-field ionization as a benchmark, we achieve a sub-8 fs FWHM instrument response function. These optical pump X-ray probe measurements enable direct observation of chemical dynamics with angstrom spatial and few-fs temporal resolution.

Weckwerth, Eleanor [Stanford University, CA (Unite↗
DOE OSTI2022

Hard exclusive $\pi^{+}n$ electro production beam spin asymmetries off the proton in the GPD and TDA regimes

Hard exclusive \pi^{+} π + n electro-production can be used to gain access to the 3D nucleon structure. The QCD factorisation mechanism in the “nearly forward region” ( t/Q^{2} t / Q 2 small) allows a description by Generalized Parton Distributions (GPDs), while for the “nearly backward” kinematic region ( u/Q^{2} u / Q 2 small) a description based on nucleon to pion transitions (TDAs) is available. The paper presents a measurement of single beam spin asymmetries to extract the A^{\sin\phi}_{LU} A L U sin ϕ moments and the related cross section ratio \sigma_{LT^\prime}/\sigma_{0} σ L T ′ / σ 0 from the hard exclusive \pi^{+} π + channel off the unpolarized hydrogen target in a wide range of kinematics based on data taken with the CLAS spectrometer at Jefferson Lab. In addition, under forward angles a detailed multidimensional study will be presented based on CLAS12 data and compared to theoretical predictions.

Diehl, Stefan↗
DOE OSTI2014

Impact of a Vertically Polarized Undulator on LCLS Hard X-ray Experiments

The LCLS-II project will install two variable gap, horizontally polarized undulators into the LCLS undulator hall. One undulator is designed to produce soft x-rays spanning an energy range of 200-1250 eV (SXU) while the other is designed for the hard spectral range of 1-25 keV (HXU). The hard x-ray LCLS instruments (X-ray Pump- Probe [XPP], X-ray correlation Spectroscopy [XCS], Coherent X-ray Imaging [CXI], Matter in Extreme Conditions [MEC]) will be repurposed to operate on the HXU line while two new soft x-ray beamlines will be created for the SXU line. An alternate HXU undulator design is being considered that could provide advantages over the present design choice. In particular, the project team is collaborating with Argonne National Laboratory to develop a vertically polarized undulator (VPU). A 1-m prototype VPU device was successfully constructed this year and a full size prototype is in process. A decision to alter the project baseline, which is the construction of a horizontally polarized device, must be made in the coming weeks to not impact the present project schedule. Please note that a change to the soft x-ray undulator is not under discussion at the moment.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2017

Commercialization of Ultra-Hard Ceramics for Cutting Tools Final Report CRADA No. TC0279.0

This was a collaborative effort between Lawrence Livermore National Security, LLC as manager and operator of Lawrence Livermore National Laboratory (LLNL) and Greenleaf Corporation (Greenleaf) to develop the technology for forming unique precursor nano-powders process that can be consolidated into ceramic products for industry. LLNL researchers have developed a solgel process for forming nano-ceramic powders. The nano powders are highly tailorable, allowing the explicit design of desired properties that lead to ultra hard materials with fine grain size. The present CRADA would allow the two parties to continue the development of the sol-gel process and the consolidation process in order to develop an industrially sound process for the manufacture of these ultra-hard materials.

36 MATERIALS SCIENCE↗
DOE OSTI2017

The Determination of Radiation Hardness of Semiconductor Materials and Devices with Ion Beams

lon accelerator based techniques provide unique tools to gain insight into the phenomena underlying the formation of defects induced by energetic particles in semiconductor materials and their effects on the electronic features of the device. In recognition of the potential of these techniques, with the aim of enhancing the understanding of the mechanisms underlying the degradation of the performances of semiconductor devices induced by ionizing radiation, the IAEA established a Research Project, coordinated by the Physics Section (CRP F11016) entitled "Utilization of ion accelerators for studying and modelling of radiation induced defects in semiconductors and insulators" at the end of 2011. The objective of this IAEA Coordinated Research Project (CRP) was to enhance the capabilities of the interested Member States by facilitating their collective efforts to use accelerator-based ion irradiation of electronic materials in conjunction with available advanced characterization techniques to gain a deeper understanding of how different types of radiation influences the electronic properties of materials and devices, leading to an improved radiation hardness. A dynamic and productive research was stimulated by this CRP among collaborating partners, resulting in publications in scientific journals [CRP2016], educational and scientific software packages [W8, Forneris2014], and a number of collaborations among the participating research groups. Two of the most significant outcomes of this project are i) the experimental protocol, which rationalizes the use of the many existing characterization techniques adopted to investigate radiation effects in semiconductor devices and ii) the relevant theoretical approach to interpret the experimental data [Vittone2016 and references therein]. This publication integrates output of research articles published by the partners of the CRP and is aimed to provide an exhaustive description of the experimental protocol, the theoretical model with the relevant limits of application, the data analysis procedure, and the physical observables which can be effectively measured and which can be used for assessment of the radiation hardness of semiconductor devices. The intended audience of this report includes all those professionals and technologists working in ion beam functional analysis of semiconductor materials, solid-state physicists and engineers involved in the design of electronic devices working in radiation harsh environments.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Medium Energy Hard X-ray FEL Gain

We develop a tool for calculation to study the conditions for a hard x-ray FEL oscillator based on electron beam in the medium enegy range from 3 to 4.5GeV. We show that the approach developed by K.J. Kim, et.al. for the small signal low gain formula can be modified so that the gain can be derived wihout taking the “no focusing approximation” adopted in the approach, so that a strong focusing can be applied. We also derive the formula to allow for gain calculation of harmonic lasing. The gain in this formula can be cast in the form of a product of two factors with one of them only depends on harmonic number, undulator period and gap. Thus this factor can be used to show that it is favorable to use harmonic lasing to achieve hard x-ray FEL working in the medium energy range and in the small signal low gain regime.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Design and Optimization of Processes for Recovering Rare Earth Elements from End-of-Life Hard Disk Drives

In this poster, we first provide motivation for why rare earth elements as rare earth permanent magnets (REPM) are increasing in demand. We then highlight some of the recent work that has been done by several national labs (National Renewable Energy Laboratory (NREL), Environmental Protection Agency (EPA), Critical Minerals Institute (CMI)) on recycling rare earth elements from end-of-life hard disk drives (EOL). Then, we mention our long-term plan to design a feedstock agnostic process to recover rare earth elements as rare earth oxides from many different EOL products at once. Next, we discuss how we quantified the rare earth elements available for recycling from EOL hard disk drives from consumer desktops and laptops. We then discuss how we used superstructure optimization to design the optimal pathway. The proposed superstructure was modeled as a MILP optimization problem, selecting the net present value as the objective function. Costing data from the literature was used to inform this model whenever possible. However, due to the novelty of this research area, data were often unavailable, thus requiring the generation of flowsheets implemented in Aspen Plus.

Laliwala, Chris↗
DOE OSTI2019

Determining the Maximum-Performance Temperature of Hard-Alloy Cutting Inserts on the Basis of Their Electromagnetic Properties

The temperature dependence of the electromagnetic properties of hard tool alloys is studied experimentally. Temperature intervals corresponding to maximum alloy performance are identified. A method is proposed for determining the maximum-performance temperature of hard-alloy cutting inserts from the temperature dependence of the electromagnetic properties.

42 ENGINEERING↗
DOE OSTI2022

RADiCAL—Precision Timing, Ultracompact, Radiation-Hard Electromagnetic Calorimetry

To address the challenges of providing high-performance calorimetry in future hadron collider experiments under conditions of high luminosity and high radiation (FCC-hh environments), we conducted R&D on advanced calorimetry techniques suitable for such operation, based on scintillation and wavelength-shifting technologies and photosensor (SiPM and SiPM-like) technology. In particular, we focused our attention on ultra-compact radiation-hard EM calorimeters based on modular structures (RADiCAL modules) consisting of alternating layers of the very dense absorber and scintillating plates, read out via radiation hard wavelength shifting (WLS) solid fiber or capillary elements to photosensors positioned either proximately or remotely, depending upon their radiation tolerance. RADiCAL modules provide the capability to measure simultaneously and with high precision the position, energy and timing of EM showers. This paper provides an overview of the instrumentation and photosensor R&D associated with the RADiCAL program.

Anderson, Thomas↗
DOE OSTI2023

Design of Monolithic Bi-Layer High-Z PAL-Si Hard X-ray CMOS Image Sensors for Quantum Efficiency Enhancement

This article experimentally investigates the inception of an innovative hard X-ray photon energy attenuation layer (PAL) to advance high-energy X-ray detection (20–50 keV). A bi-layer design with a thin film high-Z PAL on the top and Si image sensor on the bottom has previously demon-strated quantum yield enhancement via computational methods by the principle of photon energy down conversion (PEDC), where high-energy X-ray photon energies are attenuated via inelastic scattering down to ≤10 keV, which is suitable for efficient photoelectric absorption by Si. Quantum yield enhancement has been experimentally confirmed via a preliminary demonstration using PAL-integrated Si-based CMOS image sensors (Si CIS). Furthermore, substituting the high-Z PAL with a lower-Z material—Sn—and alternatively coupling it with a conventional scintillator ma-terial—Lutetium-yttrium oxyorthosilicate (LYSO)—have been compared to demonstrate the most prominent efficacy of monolithic integration of high-Z PAL on Si CIS to detect hard X-rays, paving the way for next-generation high-energy X-ray detection methods.

47 OTHER INSTRUMENTATION↗
DOE OSTI2017

AstroSat /LAXPC Observation of Cygnus X-1 in the Hard State

We report the first analysis of data from AstroSat /LAXPC observations of Cygnus X-1 in 2016 January. LAXPC spectra reveals that the source was in the canonical hard state, represented by a prominent thermal Comptonization component having a photon index of ∼1.8 and high temperature of kT{sub e} > 60 keV along with weak reflection and possible disk emission. The power spectrum can be characterized by two broad lorentzian functions centered at ∼0.4 and ∼3 Hz. The rms of the low-frequency component decreases from ∼15% at around 4 keV to ∼10% at around 50 keV, while that of the high-frequency one varies less rapidly from ∼13.5% to ∼11.5% in the same energy range. The time lag between the hard (20–40 keV) and soft (5–10 keV) bands varies in a step-like manner being nearly constant at ∼50 milliseconds from 0.3 to 0.9 Hz, decreasing to ∼8 milliseconds from 2 to 5 Hz and finally dropping to ∼2 milliseconds for higher frequencies. The time lags increase with energy for both the low and high-frequency components. The event mode LAXPC data allows for flux resolved spectral analysis on a timescale of 1 s, which clearly shows that the photon index increased from ∼1.72 to ∼1.80 as the flux increased by nearly a factor of two. We discuss the results in the framework of the fluctuation propagation model.

79 ASTRONOMY AND ASTROPHYSICS↗