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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 685 records · Page 38
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Cryogenic C-band wavelength division multiplexing system using an AIM Photonics Foundry process design kit

Cryogenic environments make superconducting computing possible by reducing thermal noise, electrical resistance and heat dissipation. Heat generated by the electronics and thermal conductivity of electrical transmission lines to the outside world constitute two main sources of thermal load in such systems. As a result, higher data rates require additional transmission lines which come at an increasingly higher cooling power cost. Hybrid or monolithic integration of silicon photonics with the electronics can be the key to higher data rates and lower power costs in these systems. We present a 4-channel wavelength division multiplexing photonic integrated circuit (PIC) built from modulators in the AIM Photonics process development kit (PDK) that operate at 25 Gbps at room temperature and 10 Gbps at 40 K. We further demonstrate 2-channel operation for 20 Gbps aggregate data rate at 40 K using two different modulators/wavelengths, with the potential for higher aggregate bit rates by utilizing additional channels.

42 ENGINEERING↗
NASA NTRS1981

Superconducting gyrocon would be very efficient

Cryogenic operation of gyrocon increases gain by more than 35 dB and efficiency by 90 percent. Device consists of electron gun, deflection cavity output cavity, collector, and output coupler. Inout and output cavities are made of superconducting lead or niobium. Gyrocon operates at frquencies up to 50 GHz.

Yen, H. C.↗
NASA NTRS2012

Overview and Status of the James Webb Space Telescope Observatory

The James Webb Space Telescope (JWST) is a large aperture (6.5 meter), cryogenic space telescope with a suite of near and mid-infrared instruments spanning the wavelength range of 0.6 microns to 28 microns. JWST's primary science goals are to detect and characterize the first galaxies, study the assembly of galaxies, star formation, and the formation of evolution of planetary systems. JWST has a unique design based on the concept of passive cooling by means of a multi-layer sunshield to achieve the telescope's cryogenic operating temperature. Each of the five layers of the sunshield is approximately the size of a tennis court, and made of aluminized kapton. By maintaining an observatory attitude whereby the sunshield keeps the telescope in the shade from the sun's rays, the telescope and science instruments can operate at cryogenic temperature (-40 K). On the sun facing side of the observatory the spacecraft bus houses most of the electronic sub-systems, and provides a platform for the solar array and communications hardware. JWST is sufficiently large that it cannot fit inside .the fairing of its Ariane 5 launcher without being stowed in a more compact configuration, so the ability to deploy its major SUb-systems such as the telescope optics and sunshield after launch are another major feature of the observatory. Development of observatory is making rapid progress as major hardware SUb-systems nearcompletion. Polishing of the JWST telescope mirrors is complete with 18 primary mirror segments, the secondary mirror, tertiary and fine steering mirror all gold coated and through acceptance testing. Engineering test articles of each sunshield membrane layer are underway. The first layer 3 membrane is complete and is undergoing testing to evaluate its tensioned shape for compliance with alignment tolerances. As each major SUb-system is tested, the expected scientific performance of the observatory can be evaluated using test results and integrated system models of the observatory. We will discuss key performance parameters of the observatory, including thermal performance, image quality, sensitivity, and the ability to achieve background-limited observations. The observatory deployment after launch will also be discussed in the context of recent sub-system testing of deployment mechanisms.

Clampin, Mark↗
NASA NTRS2015

CarbAl Heat Transfer Material

The increasing use of power electronics, such as high-current semiconductor devices and modules, within space vehicles is driving the need to develop specialty thermal management materials in both the packaging of these discrete devices and the packaging of modules consisting of these device arrays. Developed by Applied Nanotech, Inc. (ANI), CarbAl heat transfer material is uniquely characterized by its low density, high thermal diffusivity, and high thermal conductivity. Its coefficient of thermal expansion (CTE) is similar to most power electronic materials, making it an effective base plate substrate for state-of-the-art silicon carbide (SiC) super junction transistors. The material currently is being used to optimize hybrid vehicle inverter packaging. Adapting CarbAl-based substrates to space applications was a major focus of the SBIR project work. In Phase I, ANI completed modeling and experimentation to validate its deployment in a space environment. Key parameters related to cryogenic temperature scaling of CTE, thermal conductivity, and mechanical strength. In Phase II, the company concentrated on improving heat sinks and thermally conductive circuit boards for power electronic applications.

Fink, Richard↗
NASA NTRS1993

Cronstedtite and iron sulfide mineralogy of CM-type carbonaceous chondrites from cryogenic Moessbauer spectra

Determinations of oxidation states and the crystal chemistry of iron-bearing minerals in CM meteorites by Moessbauer spectroscopy are complicated by thermally-induced electron hopping in cronstedtite and by ill-defined contributions from the hydrous iron sulphide phase believed to be tochilinite. Moessbauer spectral measurements at 30 K of several cronstedtite and tochilinite specimens have enabled modal proportions of these minerals, as well as Fe(3+)/Fe(2+) ratios, to be determined quantitatively for a suite of CM-type carbonaceous chondrites that included Murchison, Murray, Cold Bokkeveld, ALH 83100, and LEW 90500.

Fisher, Duncan S.↗
DOE OSTI2026

Detectors and beam monitors based on wide bandgap semiconductors at cryogenic temperatures

Wide-bandgap semiconductors, such as single-crystal diamond and sapphire, can be used to measure the flux of passing particles through a particle-induced conductivity effect. We recently demonstrated a diamond-based, electrodeless electron beam halo monitor. This monitor utilized a thin diamond blade placed within an open, high-quality microwave resonator. The blade partially intercepted the beam and changes in the RF properties of the resonator were used to infer beam parameters. To enhance the sensitivity of our semiconductor sensors, we propose two new techniques: (1) biasing the semiconductor sensor to support avalanche multiplication of free carriers, and (2) operating at cryogenic temperatures to reduce intrinsic semiconductor losses and increase the mobility of induced carriers. These techniques are applicable not only to particle beam diagnostics but also to the detection of various types of ionizing radiation.

Accelerator Physics↗
DOE OSTI2026

Hydrogen Analysis by Gas Chromatography–Mass Spectrometry

The detection of hydrogen in complex gas mixtures is essential for many applications. Conventional approaches such as gas chromatography (GC) with thermal conductivity detection (TCD) and residual gas analyzers (RGAs) face significant limitations: TCD exhibits poor response when helium is used as a carrier gas, whereas RGAs lack chromatographic separation, preventing reliable quantification of hydrogen because of interference from other species. Traditional GC methods rely on dual-column configurations with packed or molecular-sieve porous layer open tubular (PLOT) columns to separate hydrogen from O2, N2, CO, CO2, CH4, and other hydrocarbons, increasing system complexity and limiting compatibility with mass spectrometry (MS) detection. In this work, we developed and validated a robust GC–MS method capable of directly detecting and quantifying hydrogen using electron ionization (EI) without dopants, reagent gases, or ion–molecule reaction schemes. By integrating a modified EI source and a cryogenically cooled single capillary column configuration, we achieved baseline separation of hydrogen from all major permanent gases and hydrocarbons in a refinery gas mixture using helium as the carrier gas. The method demonstrated excellent linearity, high sensitivity, and exceptional reproducibility. Adjustable sample-loop volumes and split ratios enabled optimization of peak shape and signal-to-noise performance for trace-level and percent-level hydrogen concentrations. Beyond hydrogen quantitation, the method provides simultaneous compositional profiling of other gases in a mixture in a single run, making it valuable for a wide range of tasks.

Lobodin, Vlad [ORNL]↗
DOE OSTI2020

Characterization of Amplification Properties of the Superconducting-Ferromagnetic Transistor

Here we report on the measurement results of the superconducting-ferromagnetic transistors (SFTs). The devices were made at Northwestern University and Hypres (SeeQC), Inc. (Nevirkovets et al., 2014; 2015). SFT is a multiterminal device with the SIS'FIFS (or SFIFS'IS) structure (where S, I, and F denote a superconductor, an insulator, and a ferromagnetic material, respectively) exploiting intense quasiparticle injection in order to modify the nonlinear I-V curve of a superconducting tunnel junction. SFT is capable of providing voltage, current, and power amplification while having good input/output isolation. We characterized the devices using different measurement techniques. We measured S parameters of the single- and double-acceptor devices at frequencies up to 5 MHz. Importantly, we confirmed that the isolation between the input and output of the device is quite good. However, the techniques typically employed to characterize semiconductor devices do not allow for revealing the full potential of our low-resistive SFT devices, especially those having two acceptors. In the latter case, we also tested the devices using the battery-powered current sources with floating grounds. Analyzing double-acceptor I-V curves recorded at different levels of injection currents, for an optimal load, we deduced a small-signal voltage gain of 33 and a power gain of 2.4. We suggest that further improvement of the SFT device parameters is possible in optimized devices, so that the device potentially may serve as a preamplifier for readout of output signals of cryogenic detectors and be useful as an element of other superconductor-based circuits. In addition, we used scanning transmission electron microscopy to identify some problems in the fabrication of the devices without any planarization.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2023

Cryogenic Control Circuitry for Superconducting Qubits

Superconducting qubits have reached the point where system designers are worried about the heat that control wiring brings into the cryostat. To continue scaling cryogenic quantum systems, control solutions that work inside the cold space must be explored. One possibility is to use control electronics that is native to superconductivity, so called single-flux-quantum (SFQ) circuitry, to form an interface between qubits and whatever other electronics is needed to control eventual quantum systems. To begin exploring the utility of SFQ as control circuitry, we performed modeling and experiments on qubit readout using ballistic fluxons which are SFQ in the limit of ballistic fluxon transport. Our modeling results show that a flavor of qubit, the fluxonium, can be read out using ballistic fluxons. We designed test samples to prove some of the key concepts needed for such a readout but were ultimately unable to getting a working demonstration. The lack of testing success was due to challenges in fabrication and running short of time to perform testing rather than a fundamental problem with our analysis.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
NASA NTRSDate not supplied

Update on Planetary, Lunar, & Asteroid Natural Environment Testbed (PLANET)

At ISMSE15, the Planetary, Lunar, & Asteroid Natural Environment Testbed (PLANET) was introduced as an upcoming high-fidelity, combined-effects planetary surface environment laboratory. This year, we will present an update on the facility status, describing the procurement, installation, commissioning of the chamber in Huntsville, Alabama (USA). With NASA’s push to return to the Moon through the Artemis program, there is a clear need for more high-fidelity test chambers that can replicate multiple aspects of the lunar surface, especially the fine, dusty lunar soil known as regolith. The PLANET chamber is designed to fill this gap, enabling research & development, qualification, and verification testing in a combined lunar surface environment, at an affordable price, for government, commercial/industry, and academic partners. Features include a large regolith simulant bed, low energy electron and ion sources to replicate the solar wind, full-spectrum UV and Solar simulation, and a liquid nitrogen cryogenic shroud, all in a high-vacuum environment (as low as 10^-7 mbar). PLANET’s initial focus will be on the lunar environment, but other surface environments (Martian, asteroid, etc.) are also possible to simulate. Besides the environmental instrumentation, PLANET will be equipped with specialized test systems that the Space Environmental Effects Team has developed over the past two years, including an in-situ tribometer and uniform dust distribution system. The chamber is currently being manufactured, with plans to install in May 2024. This will be followed by outfitting and commissioning. The challenges and accomplishments seen during this process will be detailed, and data from the first tests performed in PLANET will be shared with the community.

environmental testing↗
DOE OSTI2020

Dissociative Recombination of Cold HeH + Ions

The HeH + cation is the simplest molecular prototype of the indirect dissociative recombination (DR) process that proceeds through electron capture into Rydberg states of the corresponding neutral molecule. This Letter develops the first application of our recently developed energy-dependent frame transformation theory to the indirect DR processes. The theoretical model is based on the multichannel quantum-defect theory with the vibrational basis states computed using exterior complex scaling of the nuclear Hamiltonian. The ab initio electronic R-matrix theory is adopted to compute quantum defects as functions of the collision energy and of the internuclear distance. The resulting DR rates are convolved over the beam energy distributions relevant to a recent experiment at the Cryogenic Storage Ring, giving good agreement between the experiment and the theory.

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2021

The electric field dependence of single electron emission in the PIXeY two-phase xenon detector

Dual phase xenon detectors are widely used in experimental searches for galactic dark matter particles. The origin of single electron backgrounds following prompt scintillation and proportional scintillation signals in these detectors is not fully understood, although there has been progress in recent years. Here, in this paper, we describe single electron backgrounds in 83m Kr calibration events and their correlation with drift and extraction fields, using the Particle Identification in Xenon at Yale (PIXeY) dual-phase xenon time projection chamber. The single electron background induced by the Fowler-Nordheim (FN) effect is measured, and its electric field dependence is quantified. The photoionization of grids and impurities by prompt scintillation and proportional scintillation also contributes to the single electron background.

47 OTHER INSTRUMENTATION↗
NASA NTRS2004

Electron Irradiation Effects on Nanocrystal Quantum Dots Used in Bio-Sensing Applications

Effects of electron irradiation on some of the optical properties in organic CdSe nanocrystals coated in trioctylphosphine oxide (TOPO) and biologically compatible CdSe nanocrystals coated in mercaptoacetic acid, as CdSe as CdSe nanocrystals conjugated with the protein are investigated using the technique of cathodoluminescence. Effects of varying the beam energy and temperatures were examined and faster degradation at cryogenic temperatures and higher beam energies was found under some conditions.

nanocrystal↗
DOE OSTI2022

Polaronic Conductivity in Cr 2 Ge 2 Te 6 Single Crystals

We report that intrinsic 2D ferromagnetic semiconductors are an important class of materials for spin-charge conversion applications. Cr 2 Ge 2 Te 6 retains long-range magnetic order in the bilayer at cryogenic temperatures and shows complex magnetic interactions with considerable magnetic anisotropy. Here, a series of structural, magnetic, X-ray scattering, electronic, thermal transport and first-principles calculation studies are performed, which reveal that localized electronic charge carriers in Cr 2 Ge 2 Te 6 are dressed by the surrounding lattice and are involved in polaronic transport via hopping that is observed via magnetocrystalline anisotropy. This opens the possibility for manipulation of charge transport in Cr 2 Ge 2 Te 6 —based devices by electron–phonon- and spin–orbit coupling-based tailoring of polaron properties.

2D materials↗
DOE OSTI2026

Exploring Local Vibrational Structure in Protein-Bound Chlorophyll a: Isotope-Enrichment Experiments and Electrostatic Analysis

Local chlorophyll (Chl) vibrations play an essential role in biological photosynthesis by facilitating rapid energy transfer between pigments. In research studies, they also provide a useful spectroscopic probe of the local protein environment that surrounds each pigment. However, measuring the complete vibrational absorption spectrum of a protein-bound Chl molecule is much more difficult than, for example, Chl in neat solvent due to overlap with protein vibrations that typically drown out Chl vibrational features. Resonance Raman and fluorescence spectroscopies provide a way around this problem for Franck–Condon active vibrations, but these often rely on cryogenic measurement conditions and fail to capture vibrational signatures from, e.g., ester-group vibrations that lack coupling to a convenient electronic transition. In the present contribution, we use 13 C-enrichment of the protein backbone to shift protein background signals to lower frequency, providing a largely clean spectral window in which to study local Chl a C═O stretch modes. A room-temperature absorption spectrum for Chl a in the water-soluble chlorophyll protein (WSCP) of Lepidium virginicum is thus extracted as a difference between protein-plus-pigment and protein-only vibrational spectra. Excellent agreement in the molecular fingerprint region with the vibrational spectrum of Chl a in organic solvents confirms that the resulting spectrum represents the response of the protein-bound Chl a molecule. Furthermore, the ester group resonance is observed to shift in response to the S53P mutation that eliminates a 17 3 ester group hydrogen bond from the protein environment. Finally, we analyze these experimental results using MD-based electrostatic analysis, finding that electric-field mapping at the C atom of the ester group provides a satisfactory explanation for the observed frequency shifts between organic solvent and protein environment. MD analysis further suggests that a red-shifted ester peak observed experimentally for the S53P mutant results from solvation of the 17 3 Chl ester group due increase water penetration into the Chl-binding pocket relative to wild-type WSCP. Here, we anticipate that these results will prove useful both for benchmarking future simulation work and as a reference for interpreting Chl vibrational spectra as a probe of pigment–protein interactions.

14 SOLAR ENERGY↗
NASA NTRS2000

RF Single Electron Transistor Readout Amplifiers for Superconducting Astronomical Detectors for X-Ray to Sub-mm Wavelengths

We report progress on using a new type of amplifier, the Radio-Frequency Single-Electron Transistor (RF-SET), to develop multi-channel sensor readout systems for fast and sensitive readout of high impedance cryogenic photodetectors such as Superconducting Tunnel Junctions and Single Quasiparticle Photon Counters. Although cryogenic, these detectors are desirable because of capabilities not other-wise attainable. However, high impedances and low output levels make low-noise, high-speed readouts challenging, and large format arrays would be facilitated by compact, low-power, on-chip integrated amplifiers. Well-suited for this application are RF-SETs, very high performance electrometers which use an rf readout technique to provide 100 MHz bandwidth. Small size, low power, and cryogenic operation allow direct integration with detectors, and using multiple rf carrier frequencies permits simultaneous readout of 20-50 amplifiers with a common electrical connection. We describe both the first 2-channel demonstration of this wavelength division multiplexing technique for RF-SETs, and Charge-Locked-Loop operation with 100 kHz of closed-loop bandwidth.

Stevenson, Thomas↗
NASA NTRS2004

Superconducting Digital Multiplexers for Sensor Arrays

Arrays of cryogenic microbolometers and other cryogenic detectors are being developed for infrared imaging. If the signal from each sensor is amplified, multiplexed, and digitized using superconducting electronics, then this data can be efficiently read out to ambient temperature with a minimum of noise and thermal load. HYPRES is developing an integrated system based on SQUID amplifiers, a high-resolution analog-to-digital converter (ADC) based on RSFQ (rapid single flux quantum) logic, and a clocked RSFQ multiplexer. The ADC and SQUIDs have already been demonstrated for other projects, so this paper will focus on new results of a digital multiplexer. Several test circuits have been fabricated using Nb Josephson technology and are about to be tested at T = 4.2 K, with a more complete prototype in preparation.

Kadin, Alan M.↗
DOE OSTI2020

Electron Redistribution within the Nitrogenase Active Site FeMo-cofactor During Reductive Elimination of H2 to Achieve N=N Triple-Bond Activation

Nitrogen fixation by nitrogenase begins with accumulation of four reducing equivalents at the active-site FeMo-cofactor (FeMo-co), generating a state (denoted E4(4H)) with two [Fe-H-Fe] bridging hydrides. Recently, photolytic reductive elimination (re) of the E4(4H) hydrides showed that enzymatic re of E4(4H) hydride yields an H2-bound complex (E4(H2,2H)), in a process corresponding to a formal 2-electron reduction of the metal-ion core of FeMo-co. The resulting electron-density redistribution from Fe-H bonds to the metal ions themselves enables N2 to bind with concomitant H2 release, a process illuminated here by QM/MM molecular dynamics simulations. What is the nature of this redistribution? Although E4(H2,2H) hasn’t been trapped, cryogenic photolysis of E4(4H) provides a means to address this question. Photolysis of E4(4H) causes hydride-re with release of H2, generating doubly-reduced FeMo-co (denoted E4(2H)*), the extreme limit of the electron-density redistribution upon formation of E4(H2,2H). Here we examine the doubly-reduced FeMo-co core of the E4(2H)* limiting-state by 1H, 57Fe, and 95Mo ENDOR to illuminate the partial electron-density redistribution upon E4(H2,2H) formation during catalysis, complementing these results with corresponding DFT computations. Inferences from the E4(2H)* ENDOR results as extended by DFT computations include: (i) the Mo-site participates negligibly, and overall it is unlikely that Mo changes valency throughout the catalytic cycle; (ii) two distinctive E4(4H) 57Fe signals are suggested as associated with ‘anchors’ of one bridging hydride, two others with anchors of the second, with NBO-analysis identifying one anchor of each hydride as a major recipient of electrons released upon breaking Fe-H bonds.

Lukoyanov, Dmitriy↗