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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 433 records · Page 24
All sourcesNASA NTRSDOE OSTI
DOE OSTI2015

Development of a compact magnetic proton recoil spectrometer for measurement of deuterium-tritium neutrons

A new compact magnetic proton recoil (MPR) neutron spectrometer has been designed for precise measurement of deuterium-tritium (DT) neutrons. This design is presented emphasizing the magnetic analyzing system, which is based on a compact quadrupole-dipole (QD) electromagnet. The focal plane detector (FPD) is also discussed with respect to application for the next step. The characteristics of the MPR spectrometer were calculated by using Monte Carlo simulation. A preliminary experiment was performed to test the magnetic analyzing system and the proton images of the FPD. Since the QD electromagnet design allows for a larger foil thickness and solid angle to be utilized, the MPR spectrometer defined in this paper can achieve neutron detection efficiency more than 5 × 10{sup −7} at an energy resolution of 1.5% for measuring DT neutrons.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2016

Design of a portable optical emission tomography system for microwave induced compact plasma for visible to near-infrared emission lines

A new non-invasive diagnostic system is developed for Microwave Induced Plasma (MIP) to reconstruct tomographic images of a 2D emission profile. A compact MIP system has wide application in industry as well as research application such as thrusters for space propulsion, high current ion beams, and creation of negative ions for heating of fusion plasma. Emission profile depends on two crucial parameters, namely, the electron temperature and density (over the entire spatial extent) of the plasma system. Emission tomography provides basic understanding of plasmas and it is very useful to monitor internal structure of plasma phenomena without disturbing its actual processes. This paper presents development of a compact, modular, and versatile Optical Emission Tomography (OET) tool for a cylindrical, magnetically confined MIP system. It has eight slit-hole cameras and each consisting of a complementary metal–oxide–semiconductor linear image sensor for light detection. The optical noise is reduced by using aspheric lens and interference band-pass filters in each camera. The entire cylindrical plasma can be scanned with automated sliding ring mechanism arranged in fan-beam data collection geometry. The design of the camera includes a unique possibility to incorporate different filters to get the particular wavelength light from the plasma. This OET system includes selected band-pass filters for particular argon emission 750 nm, 772 nm, and 811 nm lines and hydrogen emission H{sub α} (656 nm) and H{sub β} (486 nm) lines. Convolution back projection algorithm is used to obtain the tomographic images of plasma emission line. The paper mainly focuses on (a) design of OET system in detail and (b) study of emission profile for 750 nm argon emission lines to validate the system design.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2016

Compact all-fiber quartz-enhanced photoacoustic spectroscopy sensor with a 30.72 kHz quartz tuning fork and spatially resolved trace gas detection

An ultra compact all-fiber quartz-enhanced photoacoustic spectroscopy (QEPAS) sensor using quartz tuning fork (QTF) with a low resonance frequency of 30.72 kHz was demonstrated. Such a sensor architecture has the advantages of easier optical alignment, lower insertion loss, lower cost, and more compact compared with a conventional QEPAS sensor using discrete optical components for laser delivery and coupling to the QTF. A fiber beam splitter and three QTFs were employed to perform multi-point detection and demonstrated the potential of spatially resolved measurements.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2016

Development of a compact vertical-cavity surface-emitting laser end-pumped actively Q-switched laser for laser-induced breakdown spectroscopy

This paper reports the development of a compact and portable actively Q-switched Nd:YAG laser and its applications in laser-induced breakdown spectroscopy (LIBS). The laser was end-pumped by a vertical-cavity surface-emitting laser (VCSEL). The cavity lases at a wavelength of 1064 nm and produced pulses of 16 ns with a maximum pulse energy of 12.9 mJ. The laser exhibits a reliable performance in terms of pulse-to-pulse stability and timing jitter. The LIBS experiments were carried out using this laser on NIST standard alloy samples. Shot-to-shot LIBS signal stability, crater profile, time evolution of emission spectra, plasma electron density and temperature, and limits of detection were studied and reported in this paper. The test results demonstrate that the VCSEL-pumped solid-state laser is an effective and compact laser tool for laser remote sensing applications.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2016

CHESS upgrade with compact undulator magnets: Operating experience and first results

In November 2014 two in-air 1.5 m CHESS Compact Undulator (CCU) magnets built by KYMA S.R.l. were installed in Cornell Electron Storage Ring (CESR) in canted arrangement and after few days of commissioning their regular operation started. CCU magnets are compact, lightweight and cost efficient devices. They have very stable magnetic field integrals independent of deflection parameter value. This feature greatly simplifies the storage ring operation. The CCU concept was developed at Cornell in 2011 and the first 1 m in-vacuum CCU magnet was beam-tested in 2012. The article presents CCU concept and some details of the design. It describes also the layout of CCUs installation in CESR, their performance and characteristics. The current status of operation and future plans are discussed as well. Presently, at CHESS two CCU magnets provide radiation for 5 out of 11 experimental stations.

43 PARTICLE ACCELERATORS↗
DOE OSTI2016

Development of a compact, fiber-coupled, six degree-of-freedom measurement system for precision linear stage metrology

A compact, fiber-coupled, six degree-of-freedom measurement system which enables fast, accurate calibration, and error mapping of precision linear stages is presented. The novel design has the advantages of simplicity, compactness, and relatively low cost. This proposed sensor can simultaneously measure displacement, two straightness errors, and changes in pitch, yaw, and roll using a single optical beam traveling between the measurement system and a small target. The optical configuration of the system and the working principle for all degrees-of-freedom are presented along with the influence and compensation of crosstalk motions in roll and straightness measurements. Several comparison experiments are conducted to investigate the feasibility and performance of the proposed system in each degree-of-freedom independently. Comparison experiments to a commercial interferometer demonstrate error standard deviations of 0.33 μm in straightness, 0.14 μrad in pitch, 0.44 μradin yaw, and 45.8 μrad in roll.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2016

A high speed compact microwave interferometer for density fluctuation measurements in Sino-UNIted Spherical Tokamak

A single-channel 3 mm interferometer has been developed for plasma density diagnostics in the Sino-UNIted Spherical Tokamak (SUNIST). The extremely compact microwave interferometer utilizes one corrugated feed horn antenna for both emitting and receiving the microwave. The beam path lies on the equatorial plane so the system would not suffer from beam path deflection problems due to the symmetry of the cross section. A focusing lens group and an oblique vacuum window are carefully designed to boost the signal to noise ratio, which allows this system to show good performance even with the small-diameter central column itself as a reflector, without a concave mirror. The whole system discards the reference leg for maximum compactness, which is particularly suitable for the small-sized tokamak. An auto-correcting algorithm is developed to calculate the phase evolution, and the result displays good phase stability of the whole system. The intermediate frequency is adjustable and can reach its full potential of 2 MHz for best temporal resolution. Multiple measurements during ohmic discharges proved the interferometer’s capability to track typical density fluctuations in SUNIST, which enables this system to be utilized in the study of MHD activities.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2016

Towards developing a compact model for magnetization switching in straintronics magnetic random access memory devices

Strain-mediated magnetization switching in a magnetic tunneling junction (MTJ) by exploiting a combination of piezoelectricity and magnetostriction has been proposed as an energy efficient alternative to spin transfer torque (STT) and field induced magnetization switching methods in MTJ-based magnetic random access memories (MRAM). Theoretical studies have shown the inherent advantages of strain-assisted switching, and the dynamic response of the magnetization has been modeled using the Landau-Lifshitz-Gilbert (LLG) equation. However, an attempt to use LLG for simulating dynamics of individual elements in large-scale simulations of multi-megabyte straintronics MRAM leads to extremely time-consuming calculations. Hence, a compact analytical solution, predicting the flipping delay of the magnetization vector in the nanomagnet under stress, combined with a liberal approximation of the LLG dynamics in the straintronics MTJ, can lead to a simplified model of the device suited for fast large-scale simulations of multi-megabyte straintronics MRAMs. In this work, a tensor-based approach is developed to study the dynamic behavior of the stressed nanomagnet. First, using the developed method, the effect of stress on the switching behavior of the magnetization is investigated to realize the margins between the underdamped and overdamped regimes. The latter helps the designer realize the oscillatory behavior of the magnetization when settling along the minor axis, and the dependency of oscillations on the stress level and the damping factor. Next, a theoretical model to predict the flipping delay of the magnetization vector is developed and tested against LLG-based numerical simulations to confirm the accuracy of findings. Lastly, the obtained delay is incorporated into the approximate solutions of the LLG dynamics, in order to create a compact model to liberally and quickly simulate the magnetization dynamics of the MTJ under stress. Using the developed delay equation, the efficiency of the straintronics switching over the STT method is highlighted by analytically investigating the energy-delay trade-off of both methodologies.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2017

An oil-free compact X-pinch plasma radiation source: Design and radiation performance

This paper describes a new, high-current, X-pinch radiation source recently developed and tested at Idaho State University. Our design is based on two linear transformer driver (LTD) bricks arranged in side-by-side geometry and directly coupled with an X-pinch load. The salient features of our 2-LTD-bricks are its simplicity, compactness, and portability: there is no oil, no water, and no SF6. It can be easily relocated to any place where a compact X-pinch radiation source is wanted. The driver can store up to 2.8 kJ of initial energy and can deliver more than 200-kA peak-current with less than 200-ns, 10%-90%, rise time into a short-circuit load. When the driver is coupled with an X-pinch load, it generates a very fast and bright radiation pulse. Source size measurements indicate that this radiation originates from a very small dense plasma, known as a “hot spot.”

Shapovalov, Roman V.↗
DOE OSTI2017

A compact dispersive refocusing Rowland circle X-ray emission spectrometer for laboratory, synchrotron, and XFEL applications

X-ray emission spectroscopy is emerging as an important complement to x-ray absorption fine structure spectroscopy, providing a characterization of the occupied electronic density of states local to the species of interest. Here, we present details of the design and performance of a compact x-ray emission spectrometer that uses a dispersive refocusing Rowland (DRR) circle geometry to achieve excellent performance for the 2-2.5 keV range, i.e., especially for the K-edge emission from sulfur and phosphorous. The DRR approach allows high energy resolution even for unfocused x-ray sources. This property enables high count rates in laboratory studies, approaching those of insertion-device beamlines at third-generation synchrotrons, despite use of only a low-powered, conventional x-ray tube. The spectrometer, whose overall scale is set by use of a 10-cm diameter Rowland circle and a new small-pixel complementary metal-oxide-semiconductor x-ray camera, is easily portable to synchrotron or x-ray free electron laser beamlines. Photometrics from measurements at the Advanced Light Source show excellent overall instrumental efficiency. In addition, the compact size of this instrument lends itself to future multiplexing to gain large factors in net collection efficiency or its implementation in controlled gas gloveboxes either in the lab or in an endstation.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2019

Precision Flexure Stages Design for a Compact Multilayer Laue Lens Test Bed for Hard X-ray Nanofocusing

Both the Advanced Photon Source (APS) at Argonne National Laboratory (ANL) and the Beijing Synchrotron Radiation Facility (BSRF) at Institute of High Energy Physics (IHEP) have a keen interest in the development of a compact Multilayer Laue Lens (MLL) test bed for hard x-ray nanofocusing. Recently, collaboration between ANL and IHEP, as a part of the Argonne Strategic Partnership Project (SPP) 85J05, has produced designs of precision flexure stages for a compact MLL test bed for hard x-ray nanofocusing using commercial flexural pivots and Argonne developed laminar nanopositioning flexures. Two sets of the new flexure stages will be built with the new designs, one for R&D activities at the BSRF for the new planned 6 GeV high energy photon source (HEPS) and one for upgrade of the existing MLL test bed at the APS x-ray optics test beamline. Mechanical design and preliminary test for the MLL test bed flexure stages for Argonne SPP project 85J05 are presented in this paper.

nanopositioning flexure stage↗
DOE OSTI2019

Modeling of diamond field emitter arrays for a compact source of high brightness electron beams

Many applications, such as compact accelerators and electron microscopy, demand high brightness electron beams with small source size and ultralow emittance. Diamond emitters manufactured with semiconductor processes can be employed in such compact beam sources. The micrometer-scale pyramid structure of the emitter allows enhancement of the external field compared to that at the substrate, leading to electron emission with small beam size. We investigate the dependence of the field enhancement on the shape of the emitter and the resulting emission characteristics. The beam formation and dynamics are simulated with the LSP particle-in-cell code to obtain the macroscopic observables. To account for the semiconductor charge transport in the bulk material and the tunneling through the surface, a first-principle semiclassical Monte Carlo emission model is developed and applied to the diamond pyramid. Using this Monte Carlo emission model and the result from the geometric field enhancement calculation, we construct a simple model to qualitatively explain the measured emission characteristics. In conclusion, a comparison between our model and experiments indicates that the beam current is mostly emitted at the apex of the emitter.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Compact quantum dot surface modification to enable emergent behaviors in quantum dot-DNA composites

Quantum dot (QD) biological imaging and sensing applications often require surface modification with single-stranded deoxyribonucleic acid (ssDNA) oligonucleotides. Furthermore, ssDNA conjugation can be leveraged for precision QD templating via higher-order DNA nanostructures to exploit emergent behaviors in photonic applications. Use of ssDNA-QDs across these platforms requires compact, controlled conjugation that engenders QD stability over a wide pH range and in solutions of high ionic strength. However, cur-rent ssDNA-QD conjugation approaches suffer from limitations, such as the requirement for thick coatings, low control over ssDNA labeling density, requirement of large amounts of ssDNA, or low colloidal or photostability, restraining implementation in many applications. Here, we combine thin, multidentate, phytochelatin-3 (PC3) QD passivation techniques with strain-promoted copper-free alkyne-azide click chemistry to yield functional ssDNA-QDs with high stability. This process was broadly applicable across QD sizes (i.e.,λ em = 540, 560, 600 nm), ssDNA lengths (i.e., 10–16 base pairs, bps), and sequences (poly thymine, mixed bps). The resulting compacts sDNA-QDs displayed a fluorescence quenching efficiency of up to 89% by hybridization with complementary ssDNA-AuNPs. Further-more, ssDNA-QDs were successfully incorporated with higher-order DNA origami nanostructure templates. Finally, this approach, combining PC3 passivation with click chemistry, generates ssDNA-PC3-QDs that enable emergent QD properties in DNA-based devices and applications.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2020

A compact, high resolution energy, and emittance diagnostic for electron beams using active plasma lenses

High-resolution (sub-%), single-shot energy distribution, and emittance measurements of GeV-class electron beams generated by laser plasma accelerators (LPAs) have been enabled through the use of an active plasma lens combined with relatively short dipole magnets. This setup, with only 60 cm between the LPA source and the final diagnostic screen, was facilitated through the use of a replenishable ∼20–40 nm thick liquid crystal plasma mirror to separate remnant laser radiation from the electron beam without emittance degradation. As LPAs capable of generating GeV-class electron beams at cm-scale distances become increasingly ubiquitous, there is a need to supplement these compact accelerators with equally compact diagnostics.

Barber, S. K. (ORCID:0000000172518755)↗
DOE OSTI2023

Design and construction of a compact, high-repetition-rate ultrafast electron diffraction instrument

We present the design and performance of a compact ultrafast electron diffraction instrument. The diffractometer provides a means of examining time-resolved ultrafast dynamical properties of solids. The system’s utilization is discussed in terms of instrument parameters and diffraction data from selected condensed matter samples. Here, the difractometer’s performance is highlighted in terms of detection sensitivity, instrumental temporal resolution, and the electron beam transverse coherence length. Following specific details of the construction, we present a practical discussion of parameters such as repetition rate and provide advice on general construction approaches for laboratory-based, keV ultrafast electron diffractometers. In addition, design guidance for constructing a compact electron gun source that is well-suited for studying diffraction from hard condensed matter is given. A unique data acquisition scheme, utilizing high laser repetition rates, is presented.

47 OTHER INSTRUMENTATION↗
DOE OSTI2023

Defining a compact dry cooler design to reduce LCOE contribution in a CSP facility

Concentrating solar power (CSP), when coupled with a supercritical carbon dioxide (sCO 2 ) power cycle and sensible heat storage, presents a renewable and clean alternative for utility-scale power generation. However, in order to be competitive in the current and future markets, CSP facilities must limit their levelized cost of electricity (LCOE) by minimizing capital costs and reducing operating costs over the lifetime of the plant. Targeting this goal, this study investigates the LCOE impact of the power cycle pre-cooler. This study considers a compact dry cooler with micro-channel technology on the CO 2 side and formed fin geometry on the air side, using directly-coupled centrifugal fans and a transition duct to improve air distribution across the fins as well as protect the fins from contaminants which may cause blockage, soiling, fouling, and damage. In an effort to better understand the dry cooler impact on LCOE, a sensitivity study was conducted using various combinations of end-to-end approach temperatures, air-side pressure drop values, CO 2 -side pressure drop values, fan types, cooler turndown control schemes, cooler module sizes, and design-point ambient temperatures. Furthemore, off-design cycle performance data was calculated for each dry cooler design using NPSS simulation software; cycle performance data were then input to System Advisor Model (SAM) along with the associated capital costs for LCOE prediction of a 100 MW system over a 30 year plant lifetime. Results of this study show the LCOE is most sensitive to air-side performance, followed by heat transfer effectiveness and capital cost. It was found that a power cycle with a mid- to high-performance dry cooler will produce the most competitive power-production costs. Designing at the extreme ends for approach temperature (or effectiveness), design-point ambient temperature, and compactness (footprint) produce higher LCOE values; mid-range values for these parameters balance performance, operating costs, and associated capital cost to optimize LCOE.

14 SOLAR ENERGY↗
DOE OSTI2024

General guide concepts for compact, high-brilliance neutron moderators

The trend in neutron sciences is toward integrating compact, high-brightness moderators into new or upgraded facilities. Transporting neutrons from the source to the sample position with a phase-space distribution tailored to specific requirements is crucial to leverage high source brilliance. Here we have investigated four guide concepts using Monte Carlo ray tracing simulations: Montel beamline with nested Kirkpatrick–Baez mirrors, curved-tapered beamline with a bender and straight sections, straight-elliptical beamline, and curved-elliptical beamline. The straight-elliptical (curved-elliptical) beamline features two half-ellipse guides connected by a straight (non-straight) guide section. The neutron transport efficiency and phase space homogeneity have been quantitatively compared. Our results show that the straight-elliptical beamline performs best because of few neutron bounces on the guide surface with small reflection angles, minimizing flux loss. The Montel beamline provides the best spatial confinement of neutrons within the desired region; however, there is a high thermal-neutron loss due to large reflection angles. The curved-tapered beamline suffers from significant flux loss due to high bounces, and it shows a non-uniform angular distribution related to broad ranges of bounces and reflection angles. The non-straight guide section of the curved-elliptical beamline increases the phase space inhomogeneity, leading to a spatially non-uniform beam profile. The results apply to general neutron instruments that require transporting thermal and cold neutrons from a compact, high-brilliance moderator to the sample location with a moderate phase-space volume.

47 OTHER INSTRUMENTATION↗
DOE OSTI2024

A compact and portable gamma-ray spectrometer (GRASP) for inertial confinement fusion and basic science experiments

A compact and portable gamma-ray spectrometer has been designed to diagnose different components of the inertial confinement fusion-relevant γ-ray spectrum with energies between ∼3.7–17.9 MeV. The system is designed to be as compact as possible for convenient transportation and fielding in diagnostic ports on the OMEGA laser, the National Ignition Facility, and other photon-source facilities. The system consists of a conversion foil for Compton scattering in front of four magnetic spectrometer “arms,” each covering a different energy range and constructed out of cylindrical permanent magnet Halbach arrays. Monte Carlo simulations have been used to optimize and assess the performance of the conversion foil, and COSY INFINITY ion-optical simulations have been used to optimize the spectrometer magnets. The performance of the design is assessed for a simulated direct-drive γ-ray spectrum. Spanning its total γ-ray energy bandwidth and using a 1.7 mm thick boron conversion foil, the system’s total energy resolution and efficiency are ∼15.8%–4.5% and 5.4 × 10−7–3.7 × 10−7e−/γ, respectively, with room for improvement. Spectral γ-ray measurements will provide guidance to the inertial confinement fusion program toward achieving high-energy gain relevant to inertial fusion energy and enable new measurement capabilities for basic discovery science.

Instruments & Instrumentation↗