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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 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

MCP-PMT development at Argonne for particle identification

The proposed high-energy high-luminosity polarized Electron-Ion Collider (EIC) demands excellent particle identification over a wide range of particles momenta to achieve the best separation between signal and background particles. Various Cherenkov imaging detector sub-systems are being considered in EIC detector concepts for hadron identification for particles momenta up to 50 GeV/c. One important challenge in this case is to provide a reliable highly pixelated photosensor working in the high radiation and high magnetic field environment. The recently commercialized Large Area Picosecond Photo-Detector (LAPPD) provides a promising low-cost photosensor solution for the various EIC Cherenkov imaging sub-systems. Optimization of the phtosensor design for high magnetic field tolerance, precision timing resolution, and pixelated readout was performed at Argonne National Laboratory with 6 x 6 cm(2) microchannel plate photomultipliers. The techniques and optimized design parameters would be transferrable to industrial partners for low-cost LAPPD production to achieve the demonstrated performance.

atomic layer deposition↗
DOE OSTI2024

Conceptual design of a high reactive-power ferroelectric fast reactive tuner

We present a novel design of a ferroelectric fast reactive tuner (FE-FRT) capable of modulating mega-VAR reactive power on a submicrosecond timescale. The high reactive power capability of our design extends the range of applications of reactive tuners to numerous applications. We present a detailed analytical model of the performance of a megawatt-class reactive power device and benchmark it against finite-element method eigenmode and frequency domain electromagnetic simulations. We introduce new features, including an annulus design for the ferroelectric capacitors and capacitive window coupling to the cavity. We consider thermal design issues and nonlinear effects in the ferroelectric. The model covers several configurations, allowing control of the frequency of superconducting and normal-conducting cavities in a variety of applications and frequencies. We calculate that the FE-FRT designed should be capable of handling around 0.45 MVAR of reactive power with around 3 kW of resistive losses, providing a frequency tuning range of 8 kHz in an example of 400 MHz cavity geometry. Published by the American Physical Society 2024

43 PARTICLE ACCELERATORS↗
DOE OSTI2020

Power matching to pulsed inductively coupled plasmas

Matching of power delivery to nonlinear loads in plasma processing is a continuing challenge. Plasma reactors used in microelectronics fabrication are increasingly multi-frequency and/or pulsed, producing a non-linear and, in many cases, non-steady state electrical termination that can complicate efficient power coupling to the plasma. This is particularly the case for pulsed inductively coupled plasmas where the impedance of the plasma can significantly change during the start-up-transient and undergo an E–H (capacitive-to-inductive) transition. In this paper, we discuss the results from a computational investigation of the dynamics of power matching to pulsed inductively coupled plasmas (Ar/Cl 2 mixtures of tens of mTorr pressure) using fixed component impedance matching networks and their consequences on plasma properties. In this investigation, we used set-point matching where the components of the matching network provide a best-case impedance match (relative to the characteristic impedance of the power supply) at a chosen time during the pulsed cycle. Matching impedance early during the pulse enables power to feed the E-mode, thereby emphasizing capacitive coupling and large excursions in the plasma potential. This early power coupling enables a more rapid ramp-up in plasma density while being mismatched during the H-mode later in the pulse. The early match also produces more energetic ion bombardment of surfaces. Matching late in the pulse diminishes power dissipated in the E-mode at the cost of also reducing the rate of increase in plasma density.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2020

Electrochemical reduction of europium(iii) using tetra- n -octyl diglycolamide functionalized ordered mesoporous carbon microelectrodes

This work investigates the one-electron reduction of Eu(III) to Eu(II) with ordered mesoporous carbon (OMC) in cavity microelectrode (CME) systems. OMC materials with and without tetra-n-octyl diglycolamide (TODGA) functionalization were subjected to voltammetric measurements and compared with commercial carbon black Vulcan® XC-72. The electrochemical reduction of solution Eu(III) with unfunctionalized OMC, XC-72, and TODGA-functionalized OMC—both within the electrode matrix and on the electrode surface—is reported. The complexation of Eu(III) by TODGA-functionalized OMC prior to electrode preparation incorporates Eu(III) as part of the bulk electrode matrix. Under these conditions, the high capacitance obscures the Eu(III)/Eu(II) redox couple. A signal emerges above the background (capacitive) currents when 2-octanol is added to the TODGA-functionalized OMC as a wetting agent. In contrast, surface Eu(III)–TODGA complexation, when Eu(III) contacts the electrode surface exclusively after electrode preparation, provides a strong response. The addition of 2-octanol to TODGA reduces the capacitance of the electrode and narrows the Eu(III)/Eu(II) redox peak widths. In conclusion, the desorption by reductive stripping of Eu(II) was demonstrated using a 2-octanol modified TODGA OMC CME, opening the possibility for selective separation of Eu from adjacent trivalent lanthanides.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2025

Development of a capacitance measurement for pulsed magnetic fields

Capacitance measurements are crucial for probing the electrical properties of materials. In this study, we develop and implement a capacitance measurement technique optimized for pulsed magnetic fields. Our approach employs an auto-balancing bridge method, leveraging a high-bandwidth transimpedance amplifier to mitigate parasitic contributions from coaxial cables. This technique enables precise capacitance measurements in rapidly changing magnetic fields, as demonstrated in experiments on the magnetoelectric material NiCo 2 TeO 6 . The results reveal strong magnetoelectric coupling, including a pronounced hysteresis in capacitance that coincides with magnetization measurements and an enhanced energy dissipation peak at high sweep rates. Compared to traditional LCR meter measurements in DC fields, our method exhibits excellent agreement while providing additional insight into field-induced phase transitions. This work establishes a robust methodology for capacitance measurements under extreme conditions and opens new opportunities for studying multiferroic and correlated electron systems under high magnetic fields.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2026

Parametrically amplified Josephson plasma waves in YBa 2 Cu 3 O 6+ x : Evidence for local superconducting fluctuations up to the pseudogap temperature T ∗

Experiments that subject underdoped YBa 2 Cu 3 O 6+x (YBCO) to intense terahertz pulses at temperatures between the transition temperature T c and the pseudogap scale T ∗ have revealed a reflectivity edge that resembles that of the superconducting state, together with second harmonic generation of a probe pulse modulated at a similar frequency. These have been interpreted in terms of parametric amplification of the lower Josephson plasmon mode. Since this mode is often associated with coherent oscillations between bilayers in the YBCO structure, these experiments have led to the suggestion that the intense pump has created (or revealed) in-plane pair coherence up to T ∗ ≈ 400 K. In this paper we propose an alternative explanation by assuming the existence of local pair amplitude and phase at equilibrium for T c < T < T ∗ . The phase correlation spans only a few lattice constants and we do not assume any pump-induced enhancement of this correlation, either in-plane or between bilayers. Instead, the coherent drive, via a parametric amplification process, induces coherence in the Josephson currents between members of bilayers. When combined with a Floquet framework, the reflectivity data can be explained. The key point is that in the lower Josephson plasmon, the coupling between bilayers is mainly capacitive; the Josephson current between bilayers can be set to zero without strongly affecting the parametric amplification process. Importantly, while superconducting coherence may not be created by the pump, the pseudogap phase must possess a local pairing amplitude at equilibrium. Consequently, these experiments have strong implications for the understanding of the pseudogap phase.

parametric amplification↗
DOE OSTI2024

Ferri-ionic coupling in Cu In P 2 S 6 nanoflakes: Polarization states and controllable negative capacitance

We consider nanoflakes of van der Waals ferrielectric Cu In P 2 S 6 covered by an ionic surface charge and reveal the appearance of polar states with a relatively large polarization of approximately 5 µC/ cm 2 and stored free charge of around 10 µC/ cm 2 , which can mimic “midgap” states associated with a surface-field-induced transfer of Cu and/or In ions in the van der Waals gap. The change in the ionic screening degree and mismatch strains induce a broad range of the transitions between paraelectric phase, antiferroelectric, ferrielectric, and ferri-ionic states in Cu In P 2 S 6 nanoflakes. The states’ stability and/or metastability is determined by the minimum of the system free energy consisting of electrostatic energy, elastic energy, and a Landau-type four-well potential of the ferrielectric dipole polarization. The possibility of governing the transitions by strain and ionic screening can be useful for controlling the tunneling barrier in thin-film devices based on Cu In P 2 S 6 nanoflakes. Additionally, we predict that the Cu In P 2 S 6 nanoflakes reveal features of the controllable negative capacitance effect, which make them attractive for advanced electronic devices, such as nanocapacitors and gate oxide nanomaterials with reduced heat generation. Published by the American Physical Society 2024

Physics↗
DOE OSTI2020

Surface-Mediated Interconnections of Nanoparticles in Cellulosic Fibrous Materials toward 3D Sensors

Fibrous materials serve as an intriguing class of 3D materials to meet the growing demands for flexible, foldable, biocompatible, biodegradable, dis- posable, inexpensive, and wearable sensors and the rising desires for higher sensitivity, greater miniaturization, lower cost, and better wearability. The use of such materials for the creation of a fibrous sensor substrate that interfaces with a sensing film in 3D with the transducing electronics is however difficult by conventional photolithographic methods. Here, a highly effective pathway featuring surface-mediated interconnection (SMI) of metal nanoclusters (NCs) and nanoparticles (NPs) in fibrous materials at ambient conditions is demon- strated for fabricating fibrous sensor substrates or platforms. Bimodally distrib- uted gold–copper alloy NCs and NPs are used as a model system to demonstrate the semiconductive-to-metallic conductivity transition, quantized capacitive charging, and anisotropic conductivity characteristics. Upon coupling SMI of NCs/NPs as electrically conductive microelectrodes and surface-mediated assembly (SMA) of the NCs/NPs as chemically sensitive interfaces, the resulting fibrous chemiresistors function as sensitive and selective sensors for gaseous and vaporous analytes. Finally, this new SMI–SMA strategy has significant implications for manufacturing high-performance fibrous platforms to meet the growing demands of the advanced multifunctional sensors and biosensors.

36 MATERIALS SCIENCE↗
DOE OSTI2026

Partially Ionized Plasma Physics and Technological Applications

Partially ionized plasma physics has attracted increased attention recently due to numerous technological applications made possible by the increased sophistication of computer modelling, the depth of the theoretical analysis, and the technological applications to a vast field of manufacturing for computer components. Partially ionized plasma is characterized by a significant presence of neutral particles in contrast to the fully ionized plasma. The theoretical analysis is based upon solutions of the kinetic Boltzmann equation, yielding the non-Maxwellian electron energy distribution function (EEDF), thereby emphasizing the difference with a fully ionized plasma. The impact of the effect on discharges in inert and molecular gases is described in detail, yielding the complex nonlinear phenomena resulting in plasma selforganization. A few examples of such phenomena are given, including the non-monotonic EEDFs in the discharge afterglow in a mixture of argon with the molecular gas NF3; the explosive generation of cold electron populations in capacitive discharges, hysteresis of EEDF in inductively coupled plasmas. Recently, highly advanced computer codes were developed in order to address the outstanding challenges in plasma technology. These developments are briefly described in general terms.

non-Maxwellian electron energy distribution functi↗
DOE OSTI2024

Above room temperature multiferroic and magnetoelectric properties of (1‐Φ) PZTFT‐Φ CZFMO particulate composites

Magnetoelectric (ME) composites of suitable ferroelectric and magnetic materials can display elevated magnetic and ferroelectric operational temperatures, along with substantial ME coupling, compared to conventional single-phase multiferroics. Herein, we describe the synthesis of (1-Φ) PZTFT-Φ CZFMO, Φ = 0.1, 0.2, 0.3 (PZTFT: [0.6(PbZr 0.53 Ti 0.47 O 3 )–0.4(PbFe 0.5 Ta 0.5 )O 3 ] CZFMO: Co 0.6 Zn 0.4 Fe 1.7 Mn 0.3 O 4 )] particulate (0–3) composites and report on the magnetic as well as ferroelectric phase transitions and magnetoelectric coupling. The phase formation and the induced strain in these composites are investigated via Raman spectroscopy. A large bifurcation of the zero-field cooled-field cooled magnetization curves confirms the highly anisotropic behavior of the composites. These curves also identify spin glass behavior in the CZFMO phase at ≈230 K. The magnetic phase transition of the composite (Φ = 0.2) is reported to be ≈532 (± 10) K. The temperature dependent dielectric data displays the ferroelectric phase transitions from the PZTFT phase and the broad relaxation peak from the CZFMO phase. The quadratic relationship between the magneto-capacitance and the magnetization confirms the existence of biquadratic magnetoelectric coupling in the systems. The collective results are consistent with the presence of a direct magneto-electric effect in the composites, i.e., by the application of magnetic field, the magnetic phase is strained, and this induced strain is responsible for changes of ferroelectric order parameter in the piezoelectric phase. As a result, this attribute makes the current composite structure a promising candidate for multiferroic data storage and processing technologies.

Bhoi, Krishnamayee↗
DOE OSTI2024

First demonstration of 30 eVee ionization energy resolution with RICOCHET germanium cryogenic bolometers

The future RICOCHET experiment aims to search for new physics in the electroweak sector by measuring the Coherent Elastic Neutrino-Nucleus Scattering process from reactor antineutrinos with high precision down to the sub-100 eV nuclear recoil energy range. While the RICOCHET collaboration is currently building the experimental setup at the reactor site, it is also finalizing the cryogenic detector arrays that will be integrated into the cryostat at the Institut Laue Langevin in early 2024. In this paper, we report on recent progress from the Ge cryogenic detector technology, called the CryoCube. More specifically, we present the first demonstration of a 30 eVee (electron equivalent) baseline ionization resolution (RMS) achieved with an early design of the detector assembly and its dedicated High Electron Mobility Transistor (HEMT) based front-end electronics with a total input capacitance of about 40 pF. This represents an order of magnitude improvement over the best ionization resolutions obtained on similar phonon-and-ionization germanium cryogenic detectors from the EDELWEISS and SuperCDMS dark matter experiments, and a factor of three improvement compared to the first fully-cryogenic HEMT-based preamplifier coupled to a CDMS-II germanium detector with a total input capacitance of 250 pF. Additionally, we discuss the implications of these results in the context of the future RICOCHET experiment and its expected background mitigation performance.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2021

Decoupling Proton and Cation Contributions to Capacitive Charge Storage in Birnessite in Aqueous Electrolytes

Abstract Nanostructured birnessite is of interest as an electrode material for aqueous high power electrochemical energy storage as well as desalination devices. In neutral pH aqueous electrolytes, birnessite exhibits a capacitive response attributed to the adsorption of cations and protons at the outer surface and within the hydrated interlayer. Here, we utilize the understanding of proton‐coupled electron transfer (PCET) in buffered electrolytes to decouple the role of protons and cations in the capacitive charge storage mechanism of birnessite at neutral pH. We find that without buffer, birnessite exhibits primarily potential‐independent (capacitive) behavior with excellent cycling stability. Upon the addition of buffer, the capacity initially increases and the cyclic voltammograms become more potential‐dependent, features attributed to the presence of PCET with the birnessite. However, long‐term cycling in the buffered electrolyte leads to significant capacity fade and dissolution, which is corroborated through ex situ characterization. ReaxFF atomistic scale simulations support the observations that proton adsorption leads to birnessite degradation and that capacitive charge storage in birnessite is primarily attributed to cation adsorption at the outer surface and within the interlayer.

Saeed, Saeed↗
DOE OSTI2020

ADMX SLIC: Results from a Superconducting $\textit{LC}$ Circuit Investigating Cold Axions

Axions are a promising cold dark matter candidate. Haloscopes, which use the conversion of axions to photons in the presence of a magnetic field to detect axions, are the basis of microwave cavity searches such as the Axion Dark Matter eXperiment (ADMX). To search for lighter, low frequency axions in the sub-2 × 10 –7 eV (50 MHz) range, a tunable lumped-element $\textit{LC}$ circuit has been proposed. For the first time, through ADMX SLIC (Superconducting $\textit{LC}$ Circuit Investigating Cold Axions), a resonant $\textit{LC}$ circuit was used to probe this region of axion mass-coupling space. The detector used a superconducting $\textit{LC}$ circuit with piezoelectric driven capacitive tuning. The axion mass and corresponding frequency ranges 1.7498–1.7519 × 10 –7 eV (42.31–42.36 MHz), 1.7734–1.7738 × 10 –7 eV (42.88–42.89 MHz), and 1.8007–1.8015 × 10 –7 eV (43.54–43.56 MHz) were covered at magnetic fields of 4.5 T, 5.0 T, and 7.0 T, respectively. Exclusion results from the search data, for coupling below 10 –12 GeV –1 , are presented.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2020

GaN‐based split phase transformer‐less PV inverter with auxiliary ZVT circuit

This paper explores performance enhancement of the common ground dynamic dc‐link (CGDL) inverter for single phase photovoltaic (PV) applications by a combination of gallium nitride (GaN) devices, split phase topology, coupled inductors, and zero voltage transition (ZVT) scheme. The CGDL inverter has the inherent advantage of minimised dc‐link capacitance and negligible leakage current due to the common ground configuration, but its reported efficiency was usually lower because of the higher dc‐link voltage used for the reduction of decoupling capacitance to a great extent. To solve the efficiency problem, in this study, a soft switching circuit is proposed for the first stage, while a coupled inductor integrated magnetics is incorporated in the second stage to reduce inductor loss, volume, and cost. Both of these topological improvements combined with the use of GaN devices facilitate in achieving high efficiency without compromising converter power density. Extensive experimental results are provided from a GaN based 1 kVA hardware prototype to demonstrate the superior performance of the CGDL inverter attaining a peak efficiency of 98.7% and a California Energy Commission efficiency of 98.5% at 75/50 kHz switching frequency.

Xia, Yinglai↗
DOE OSTI2021

Capacitive wireless power transfer circuit and related techniques

Capacitive wireless power transfer systems are provided. In one embodiment, for example, the system comprises two pair of coupled conducting plates; a first matching network coupled to the first pair of conducting plates; and a second matching network coupled to the second pair of conducting plates. At least one of the first and second matching networks comprises an inductor having inductance value selected based on at least one parasitic capacitance value of the capacitive wireless power transfer system. In another embodiment, a method of designing a capacitive wireless power transfer system is provided comprising determining a parasitic capacitance value of a capacitive wireless power transfer system and determining an inductance value of an inductor of at least one of the first and second matching network having a value selected based on at least one parasitic capacitance value of the capacitive wireless power transfer system.

Afridi, Khurram K.↗
DOE OSTI2020

Reducing the Susceptibility of Lumped-Element KIDs to Two-Level System Effects

Arrays of lumped-element kinetic inductance detectors (LEKIDs) optically coupled through an antenna-coupled transmission line are a promising candidate for future cosmic microwave background experiments. However, the dielectric materials used for the microstrip architecture are known to degrade the performance of superconducting resonators. In this paper, we investigate the feasibility of microstrip coupling to a LEKID, focusing on a systematic study of the effect of depositing amorphous silicon nitride on a LEKID. The discrete and spatially separated inductive and capacitive regions of the LEKID allow us to vary the degree of dielectric coverage and determine the limitations of the microstrip coupling architecture. We show that by careful removal of dielectric from regions of high electric field in the capacitor, there is minimal degradation in dielectric loss tangent of a partially covered lumped-element resonator. We present the effects on the resonant frequency and noise power spectral density and, using the dark responsivity, provide an estimate for the resulting detector sensitivity.

47 OTHER INSTRUMENTATION↗