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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 955 records · Page 53
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

SYNCA: A Synthetic Cyclotron Antenna for the Project 8 Collaboration

Cyclotron Radiation Emission Spectroscopy (CRES) is a technique for measuring the kinetic energy of charged particles through a precision measurement of the frequency of the cyclotron radiation generated by the particle's motion in a magnetic field. The Project 8 collaboration is developing a next-generation neutrino mass measurement experiment based on CRES. One approach is to use a phased antenna array, which surrounds a volume of tritium gas, to detect and measure the cyclotron radiation of the resulting β-decay electrons. To validate the feasibility of this method, Project 8 has designed a test stand to benchmark the performance of an antenna array at reconstructing signals that mimic those of genuine CRES events. To generate synthetic CRES events, a novel probe antenna has been developed, which emits radiation with characteristics similar to the cyclotron radiation produced by charged particles in magnetic fields. This paper outlines the design, construction, and characterization of this Synthetic Cyclotron Antenna (SYNCA). Furthermore, we perform a series of measurements that use the SYNCA to test the position reconstruction capabilities of the digital beamforming reconstruction technique. Finally, we find that the SYNCA produces radiation with characteristics closely matching those expected for cyclotron radiation and reproduces experimentally the phenomenology of digital beamforming simulations of true CRES signals.

47 OTHER INSTRUMENTATION↗
DOE OSTI2018

Magnetic Field Angular Dependence of Magnetization Loss in ReBCO Superconducting Tapes

In the applications of high-temperature superconductors (HTS), the HTS tapes are usually exposed to the external magnetic field with different orientations. The critical current and AC loss are affected by both the field amplitude and field angles due to the anisotropy of HTS tapes. In this work, we first introduce the experimental system to measure the magnetization loss in HTS tapes based on the calibration-free method. Then, we present the magnetization loss results in 4.8-mm-wide AMSC wire, 4-mm-wide SuperPower wire, 4-mm-wide SuNam wire, and 10-mm-wide Fujikura wire in a perpendicular applied field at 77 K. The field amplitude is up to 100 mT, and the frequency varies from 44.2 to 87.1 Hz. We also present the magnetization loss in AMSC wire, SuperPower wire, SuNam wire, and Fujikura wire at different field angles. The field angle varies from 10 to 90 {sup ∘} in 10 {sup ∘} steps. The loss reduction with the decreasing of the field angle shows the anisotropic property of HTS tapes. We finally plot the measured magnetization loss of the samples as a function of the magnetic field amplitude normalized by the field angle to verify an empirical formula.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2019

Impact Damage Investigation on Glass Fiber-Reinforced Plate Laminates at Room and Lower Temperatures through Ultrasound Testing and Electronic Speckle Pattern Interferometry

In this work, the evaluation of damage area due to low-velocity impact tests at different impact energy values and different temperatures on glass fiber-reinforced plate laminates was investigated by two nondestructive evaluation (NDE) techniques, electronic speckle pattern interferometry (ESPI) and ultrasound testing (UT). Composites are characterized by several interacting failure modes such as matrix breakage, fiber failure and delaminations, which can be simultaneously induced by low-velocity impacts and can be different depending on the temperature. It can be complicated to detect by visual inspections of the structures for such phenomena. This paper aims to investigate the dependence of the damaged area with respect to temperature variation on glass fiber composite laminates. GF composite laminates were impacted with three energy levels (5, 10, 20 J) and at different temperatures (room temperature, − 25, − 50 °C) by a drop weight impact machine. The results show that at decreasing temperature, a decrease in the damage extension was observed, which is more evident at increasing impact energy. Moreover, as expected, the results confirm UT and ESPI techniques are able to identify the barely visible low-velocity impact damage. However, some limitations for detection were found in ESPI. Nonetheless, the ESPI technique can be considered as one of the useful NDE methods if the calibration and the post-processing methods are improved.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Gap-filling eddy covariance methane fluxes: Comparison of machine learning model predictions and uncertainties at FLUXNET-CH4 wetlands

Time series of methane fluxes measured by eddy-covariance require gap-filling to estimate annual emissions. Gap-filling methane fluxes is challenging because of high variability and complex responses to multiple drivers. To date, there is no widely established gap-filling standard for methane, with regards both to the best model algorithms and predictors. In this study, we address the need for standardization by synthesizing results of gap-filling methods applied at 17 wetland sites spanning boreal to tropical regions including all major wetlands classes and two rice paddies. We introduce new procedures for: 1) creating realistic artificial gap scenarios, 2) training and evaluating gap-filling models without overstating performance, and 3) predicting half-hourly methane fluxes and annual emissions with robust uncertainty estimates. We tested a conventional method (marginal distribution sampling) and four machine learning algorithms - penalized linear regression, artificial neural networks, random forests, and boosted decision trees - and four predictor sets, including temporal, meteorological, ecosystem carbon and energy flux, and soil predictors. We find that the conventional method can achieve similar median performance to the machine learning models but is worse than the best machine learning models and relatively insensitive to predictor choices. Of the machine learning models, decision tree algorithms performed the best in cross-validation experiments, even with a baseline predictor set, and artificial neural networks showed comparable performance when using all predictors. Soil temperature was frequently the most important predictor whilst water table depth was important at sites with substantial water table fluctuations, highlighting the value of data on soil conditions. Raw gap-filling uncertainties from the machine learning models were underestimated and we propose a method to calibrate uncertainties to observations. Finally, we gap-fill and provide summary evaluation metrics for all 81 sites in the FLUXNET-CH4 community dataset and publicly release the python code for model development, evaluation, and uncertainty estimation.

42 ENGINEERING↗
DOE OSTI2014

A compact ultra-clean system for deploying radioactive sources inside the KamLAND detector

We describe a compact, ultra-clean device used to deploy radioactive sources along the vertical axis of the KamLAND liquid-scintillator neutrino detector for purposes of calibration. The device worked by paying out and reeling in precise lengths of a hanging, small-gauge wire rope (cable); an assortment of interchangeable radioactive sources could be attached to a weight at the end of the cable. All components exposed to the radiopure liquid scintillator were made of chemically compatible UHV-cleaned materials, primarily stainless steel, in order to avoid contaminating or degrading the scintillator. To prevent radon intrusion, the apparatus was enclosed in a hermetically sealed housing inside a glove box, and both volumes were regularly flushed with purified nitrogen gas. Finally, an infrared camera attached to the side of the housing permitted real-time visual monitoring of the cable’s motion, and the system was controlled via a graphical user interface.

42 ENGINEERING↗
DOE OSTI2020

CsI calorimeter for the J-PARC KOTO experiment

An electromagnetic calorimeter made of undoped CsI crystals is used in the J-PARC KOTO experiment to search for new physics beyond the standard model with the KL → π 0 νν¯ decay. The calorimeter is designed to operate in vacuum of 0.1 Pa and in a high-rate environment where the counting rate due to KL decays is O(100) kHz. A special method to calibrate the calorimeter during the data taking without using a tracking system for charged particles is reported. The energy, position, and timing resolutions of the calorimeter were evaluated in several beam tests, and the resolutions satisfy the required performance. Finally, the energy resolution with the total energy E is 0.66 ⊕ 1.81/ √ E[GeV]% in the inner region of the calorimeter.

47 OTHER INSTRUMENTATION↗
DOE OSTI2020

Performance of position-sensitive resistive silicon detectors in the Forward Array Using Silicon Technology (FAUST)

The silicon telescopes of the Forward Array Using Silicon Technology (FAUST) have been recently upgraded with silicon detectors which use resistive charge-splitting to measure the position of charged particles. This is in addition to the measurement of the total energy that these charged particles deposit in the detector. The upgrade results in increased angular resolution with a much smaller number of signals than silicon strip detectors with similar resolution. Here, a novel method of calibration has been used to demonstrate the efficacy of these position-sensitive detectors, and the detectors have been used in a commissioning experiment.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2013

Compact low resolution spectrograph, an imaging and long slit spectrograph for robotic telescopes

The COmpact LOw REsolution Spectrograph (COLORES) is a compact and lightweight (13 kg) f/8 imaging spectrograph designed for robotic telescopes, now installed and operating on the TELMA, a rapid-slewing 60 cm telescope of the BOOTES-2 observatory in Málaga (Spain). COLORES is a multi-mode instrument that enables the observer to seamlessly switch between low-dispersion spectroscopy and direct imaging modes during an observation. In this paper, we describe the instrument and its development, from the initial scientific requirements through the optical design process to final configuration with theoretical performance calculations. The mechanical and electronic design is described, methods of calibration are discussed and early laboratory and scientific results are shown.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2014

Resolving small signal measurements in experimental plasma environments using calibrated subtraction of noise signals

The performance of many diagnostic and control systems within fusion and other fields of research are often detrimentally affected by spurious noise signals. This is particularly true for those (such as radiation or particle detectors) working with very small signals. Common sources of radiated and conducted noise in experimental fusion environments include the plasma itself and instrumentation. The noise complicates data analysis, as illustrated by noise on signals measured with the heavy ion beam probe (HIBP) installed on the Madison Symmetric Torus. The noise is time-varying and often exceeds the secondary ion beam current (in contrast with previous applications). Analysis of the noise identifies the dominant source as photoelectric emission from the detectors induced by ultraviolet light from the plasma. This has led to the development of a calibrated subtraction technique, which largely removes the undesired temporal noise signals from data. The advantages of the technique for small signal measurement applications are demonstrated through improvements realized on HIBP fluctuation measurements.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2015

Visualization and quantification of magnetic nanoparticles into vesicular systems by combined atomic and magnetic force microscopy

We report a phenomenological approach for the quantification of the diameter of magnetic nanoparticles (MNPs) incorporated in non-ionic surfactant vesicles (niosomes) using magnetic force microscopy (MFM). After a simple specimen preparation, i.e., by putting a drop of solution containing MNPs-loaded niosomes on flat substrates, topography and MFM phase images are collected. To attempt the quantification of the diameter of entrapped MNPs, the method is calibrated on the sole MNPs deposited on the same substrates by analyzing the MFM signal as a function of the MNP diameter (at fixed tip-sample distance) and of the tip-sample distance (for selected MNPs). After calibration, the effective diameter of the MNPs entrapped in some niosomes is quantitatively deduced from MFM images.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Making inertial confinement fusion models more predictive

Computer models of inertial confinement fusion (ICF) implosions play an essential role in experimental design and interpretation as well as our understanding of fundamental physics under the most extreme conditions that can be reached in the laboratory. Building truly predictive models is a significant challenge, with the potential to greatly accelerate progress to high yield and ignition. One path to more predictive models is to use experimental data to update the underlying physics in a way that can be extrapolated to new experiments and regimes. We describe a statistical framework for the calibration of ICF simulations using data collected at the National Ignition Facility (NIF). We perform Bayesian inferences for a series of laser shots using an approach that is designed to respect the physics simulation as much as possible and then build a second model that links the individual-shot inferences together. We show that this approach is able to match multiple X-ray and neutron diagnostics for a whole series of NIF “BigFoot” shots. Within the context of 2D radiation hydrodynamic simulations, our inference strongly favors a significant reduction in fuel compression over other known degradation mechanisms (namely, hohlraum issues and engineering perturbations). This analysis is expanded using a multifidelity technique to pick fuel-ablator mix from several candidate causes of the degraded fuel compression (including X-ray preheat and shock timing errors). Finally, we use our globally calibrated model to investigate the extra laser drive energy that would be required to overcome the inferred fuel compression issues in NIF BigFoot implosions.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2021

Intrinsic quality factor extraction of multi-port cavity with arbitrary coupling

In this work, we derived S-parameter based expressions for the intrinsic quality factor of an arbitrary coupled multiport microwave cavity and a non-ideal test fixture. Practical accuracy limitations of the obtained expressions specifically for superconducting accelerator cavities were evaluated both analytically and with the simulation software. The resulting formulas can be used to extract the intrinsic quality factor of normal-conducting and superconducting cavities directly from the calibrated S-parameter measurements.

43 PARTICLE ACCELERATORS↗
DOE OSTI2020

Characterization of the pressure coefficient of manganin and temperature evolution of pressure in piston-cylinder cells

Here, we report measurements of the temperature- and pressure-dependent resistance, R ( T , p ), of a manganin manometer in a 4 He-gas pressure setup from room temperature down to the solidification temperature of 4 He ( T solid ~ 50 K at 0.8 GPa) for pressures, p , between 0 GPa and ~0.8 GPa. The same manganin wire manometer was also measured in a piston-cylinder cell (PCC) from 300 K down to 1.8 K and for pressures between 0 GPa and ~2 GPa. From these data, we infer the temperature and pressure dependence of the pressure coefficient of manganin, α ( T , p ), defined by the equation R p = (1 + αp ) R 0 , where R 0 and R p are the resistances of manganin at ambient pressure and finite pressure, respectively. Our results indicate that upon cooling, α first decreases, then goes through a broad minimum at ~120 K, and increases again toward lower temperatures. In addition, we find that α is almost pressure-independent at T ≳ 60 K up to p ~ 2 GPa, but shows a pronounced p dependence at T ≲ 60 K. Using this manganin manometer, we demonstrate that p overall decreases with decreasing temperature in the PCC for the full pressure range and that the size of the pressure difference between room temperature and low temperatures ( T = 1.8 K), Δ p , decreases with increasing pressure. We also compare the pressure values inferred from the manganin manometer with the low-temperature pressure, determined from the superconducting transition temperature of elemental lead (Pb). As a result of these data and analysis, we propose a practical algorithm to infer the evolution of pressure with temperature in a PCC.

47 OTHER INSTRUMENTATION↗
DOE OSTI2021

Absolute calibration of the Lyman-α measurement apparatus at DIII-D

The LLAMA (Lyman-Alpha Measurement Apparatus) diagnostic was recently installed on the DIII-D tokamak [Rosenthal et al., Rev. Sci. Instrum. (submitted) (2020)]. LLAMA is a pinhole camera system with a narrow band Bragg mirror, a bandpass interference filter, and an absolute extreme ultraviolet photodiode detector array, which measures the Ly-α brightness in the toroidal direction on the inboard, high field side (HFS) and outboard, low field side (LFS). This contribution presents a setup and a procedure for an absolute calibration near the Ly-α line at 121.6 nm. The LLAMA in-vacuum components are designed as a compact, transferable setup that can be mounted in an ex situ vacuum enclosure that is equipped with an absolutely calibrated Ly-α source. The spectral purity and stability of the Ly-α source are characterized using a vacuum ultraviolet spectrometer, while the Ly-α source brightness is measured by a NIST-calibrated photodiode. The non-uniform nature of the Ly-α source emission was overcome by performing a calibration procedure that scans the Ly-α source position and employs a numerical optimization to determine the emission pattern. Nominal and measured calibration factors are determined and compared, showing agreement within their uncertainties. A first conversion of the measured signal obtained from DIII-D indicates that the Ly-α brightness on the HFS and LFS is on the order of 1020 Ph sr-1 m-2 s-1. The established calibration setup and procedure will be regularly used to re-calibrate the LLAMA during DIII-D vents to monitor possible degradation of optical components and detectors.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2021

Absolute throughput calibration of multiple spherical crystals for the Orion High-REsolution X-ray spectrometer (OHREX)

We present absolute throughput analysis of several crystals for the Orion High-REsolution X-ray (OHREX) imaging crystal spectrometer using ray tracing and experimental measurements. The OHREX spectrometer is a high-resolution x-ray spectrometer designed to measure spectral line shapes at the Orion laser facility. The spectrometer is fielded with up to two spherical crystals simultaneously covering two independent spectral ranges. Each crystal has a nominal radius of curvature of R = 67.2 cm and is fielded at a nominal Bragg angle of 51.3°. To cover different bands of interest, several different crystals are available, including Ge (111), KAP, and several cuts of quartz, whose resolving power λ/Δλ exceeds 10 000. The calibrated response of the available crystals has previously been reported from measurements at the EBIT-I electron beam ion trap at Lawrence Livermore National Laboratory. Here, we model the absolute throughput of each crystal using ray tracing and verify the results using experimental data for the quartz $(10\bar{1}1)$ crystal.

47 OTHER INSTRUMENTATION↗
DOE OSTI2022

Development of a hardened THz energy meter for use on the kilojoule-scale, short-pulse OMEGA EP laser

A highly adaptable and robust terahertz (THz) energy meter is designed and implemented to detect energetic THz pulses from high-intensity (>10 18 W/cm 2 ) laser–plasma interactions on the OMEGA EP. THz radiation from the laser driven target is detected by a shielded pyrometer. A second identical pyrometer is used for background subtraction. The detector can be configured to detect THz pulses in the 1 mm to 30 μm (0.3- to 10-THz) range and pulse energies from joules to microjoules via changes in filtration, aperture size, and position. Additional polarization selective filtration can also be used to determine the THz pulse polarization. The design incorporates significant radiation and electromagnetic pulse shielding to survive and operate within the OMEGA EP radiation environment. We describe the design, operational principle, calibration, and testing of the THz energy meter. The pyrometers were calibrated using a benchtop laser and show linear sensitivity to up to 1000 nJ of absorbed energy. Furthermore, the initial results from four OMEGA EP THz experiments detected up to ~15 μJ at the detector, which can correspond to hundreds of mJ depending on THz emission and reflection models.

47 OTHER INSTRUMENTATION↗
DOE OSTI2023

Development of the high energy engineering X-ray (HEX) superconducting wiggler, magnetic measurement, installation, and commissioning

The High energy Engineering X-ray (HEX) diffraction beamline at the National Synchrotron Light Source II (NSLS-II) at Brookhaven National Lab (BNL) is the first high-energy beamline capable of reaching 200 keV for a monochromatic beam. With the 3 GeV electron beam energy for the NSLS-II ring, only the superconducting wiggler (SCW) producing greater than 4 T peak field can cover these ranges with a sufficient number of photons. The 1.2 m-long HEX-SCW has a period length of 70 mm and a field strength on-axis of 4.3 T. It utilizes no liquid helium, and the vertical aperture size of the electron beam vacuum chamber is 8 mm. Unlike regular undulators/wigglers, there is no standard configuration for the magnetic measurement system for superconducting insertion devices. The NSLS-II Insertion Devices group has developed, in collaboration with the vacuum group, a novel in-vacuum Hall mapper with a 1.75 m in-vacuum linear motor and an in-vacuum flip coil system utilizing many commercial-off-the-shelf products. The measurements were conducted at the BNL, and the device was installed in the ring and commissioned. Here, this paper provides a description of the SCW and its magnetic measurement systems, as well as a brief account of the installation and commissioning efforts.

36 MATERIALS SCIENCE↗