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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 235 records · Page 13
All sourcesNASA NTRSDOE OSTI
NASA NTRS2023

Using the Potassium-Argon Laser Experiment (KArLE) to Date Ancient, Low-K Chondritic Meteorites

Several laboratories have been investigating the feasibility of in situ K-Ar dating for use in future landing planetary missions. One drawback of these laboratory demonstrations is the insufficient analogy of the analyzed analog samples with expected future targets. We present the results obtained using the K-Ar laser experiment (KArLE) on two old and K-poor chondritic samples, Pułtusk and Hvittis, as better lunar analogs. The KArLE instrument uses laser ablation to vaporize rock samples and quantifies K content by laser-induced breakdown spectroscopy (LIBS), Ar by quadrupole mass spectrometry (QMS), and ablated mass by laser profilometry. We performed 64 laser ablations on the chondrites to measure spots with a range of K 2 O and Ar content and used the data to construct isochrons to determine the chondrite formation age. The KArLE isochron ages on Pułtusk and Hvittis are 5059 ± 892 Ma and 4721 ± 793 Ma, respectively, which is within the uncertainty of published reference ages, and interpreted as the age of their formation. The uncertainty (2σ) on the KArLE ages obtained in this study is better than 20% (18% for Pułtusk and 17% for Hvittis). The precision, which compares our obtained ages to the reference ages, is also better than 20% (11% for Pułtusk and 4% for Hvittis). These results are encouraging for understanding the limits of this technique to measure ancient planetary samples and for guiding future improvements to the instrument.

Fanny Cattani↗
DOE OSTI2020

Diagnosing Field Strengths and Plasma Conditions in Magnetically Insulated Transmission Lines Using Active Dopant Spectroscopy

Experimental validation data is needed to inform simulations of large pulsed power devices which are in development to understand and improve existing accelerators and inform future pulsed power capabilities. Using current spectroscopic techniques on the Z-machine, we have been unable to reliably diagnose plasma conditions and electric and magnetic fields within power flow regions. Laser ablation of a material produces a low density plasma, resulting in narrow spectroscopic line widths. By introducing a laser ablated plasma to the anode cathode gap of the Mykonos accelerator, we can monitor how the line shapes change due the current pulse by comparing these line shapes to spectral measurements taken without power flow. In this report we show several examples of measurements conducted on Mykonos on various dopant materials. We also show a negligible effect on power flow due to the presence of the ablation plasma for a range of parameters.

43 PARTICLE ACCELERATORS↗
NASA NTRS1997

Charge Transfer Between Ground-State Si(3+) and He at Electron-Volt Energies

The charge-transfer rate coefficient for the reaction Si(3+)(3s(sup 2)S) + He yields products is measured by means of a combined technique of laser ablation and ion storage. A cylindrical radio-frequency ion trap was used to store Si(3+) ions produced by laser ablation of solid silicon targets. The rate coefficient of the reaction was derived from the decay rate of the ion signal. The measured rate coefficient is 6.27(exp +0.68)(sub -0.52) x 10(exp -10)cu cm/s at T(sub equiv) = 3.9 x 10(exp 3)K. This value is about 30% higher than the Landau-Zener calculation of Butler and Dalgarno and is larger by about a factor of 3 than the recent full quantal calculation of Honvault et al.

Fang, Z.↗
DOE OSTI2022

Satellite Enveloped with STITCHED Engineering Sensors for Detection of Approaching Objects

Today as well as tomorrows spaceborne assets impact almost all areas of national and nuclear security. Spaceborne assets can not only collect and disseminate valuable data, well beyond just the visual, but also track terrestrial-based mobile assets in real-time, and active spaceborne platforms potentially pose serious risk to vulnerable earth-based systems and infrastructures. The capability to defend national spaceborne assets from attack/interference is critical for security interests. This effort supports this mission through the cost-effective preeminent detection of approaching threats to our nation’s vital resources, in order to help secure and trust these high-value assets against the threats of tomorrow. This project develops novel fabrication techniques for conformal, low-profile and lightweight leakywave antenna (LWA) detection/imaging systems, which fuses technical embroidery (TE) and laser ablation (LA) processes with LWA design. Technical embroidery is an emerging field in additive textile manufacturing where flexible materials and functionalized fabrics are created for a wide variety of uses and purposes, while laser ablation is the process of removing material from a solid surface by irradiating it with a laser beam. Here, thin, conformal antenna designs are designed, modeled and fabricated using both TE and LA, to create lightweight, flexible and conformal object detection and imaging radars. This novel development ensures our nation’s ability to field advanced lightweight and conformal technologies to protect spaceborne assets.

42 ENGINEERING↗
NASA NTRS2017

Diffusivities of Redox-Sensitive Elements in Basalt vs. Oxygen Fugacity Determined by LA-ICP-MS

Several diffusion experiments were conducted in a piston cylinder device across a range of oxygen fugacities (FMQ-3 FMQ-1.2, FMQ+6) at 1 GPa and 1300 C. This was done to explore the effects of oxygen fugacity (fO2) on diffusivity of redox sensitive trace elements. This allows investigation of how these elements diffuse across the fO2 range encountered in different reservoirs on planets and moons in our solar system. The University of Rochester LA-ICP-MS system was used for analysis of samples. Analyses were conducted using an Agilent 7900 quadrupole mass spectrometer connected to a Photon Machines 193 nm G2 laser ablation (LA) system equipped with a HelEx 2-volume sample chamber. Spots used were 35 micrometers circles spaced at 65 micrometers intervals. Laser fluence was 7.81 J/cm^2 with a rep rate of 10 Hz. The iolite software package was used to reduce data collected from laser ablation analysis of experiments with Si-29 used as the internal standard isotope. Iolite's global fit module was used to simultaneously fit elements' diffusivities in each experiment while keeping the Matano interface constant. Elements analysed include V, Nb, W, Mo, La, Ce, Pr, Sm, Eu, Gd, Ta, and W. Figures

Szumila, Ian↗
NASA NTRS1990

Photoresponse of YBa2Cu3O(7-delta) granular and epitaxial superconducting thin films

The response is reported of thin films of YBa2Cu3O(7-delta) with either a very grainy or a smooth epitaxial morphology to visible radiation. SrTiO3 substrates were employed for both types of films. The grainy films were formed by sequential multi-layer electron beam evaporation while the epitaxial films were formed by laser ablation. Both films were patterned into H shaped detectors via a negative photolithographic process employing a Br/ethanol etchant. The bridge region of the H was 50 microns wide. The patterned films formed by laser ablation and sequential evaporation had critical temperatures of 74 K and 72 K respectively. The bridge was current biased and illuminated with chopped He-Ne laser radiation and the voltage developed in response to the illumination was measured. A signal was detected only above the critical temperature and the peak of the response coincided with the resistive transition for both types of films although the correspondence was less exact for the grainy film. The details of the responses and their analysis are presented.

Valco, G. J.↗
NASA NTRS1990

Photoresponse of YBa2Cu3O(7-delta) granular and epitaxial superconducting thin films

The response is reported of thin films of YBa2Cu3O(7-delta) with either a very grainy or a smooth epitaxial morphology to visible radiation. SrTiO3 substrates were employed for both types of films. The grainy films were formed by sequential multi-layer electron beam evaporation while the epitaxial films were formed by laser ablation. Both films were patterned into H shaped detectors via a negative photolithographic process employing a Br/ethanol etchant. The bridge region of the H was 50 microns wide. The patterned films formed by laser ablation and sequential evaporation had critical temperatures of 74 K and 72 K respectively. The bridge was current biased and illuminated with chopped He-Ne laser radiation and the voltage developed in response to the illumination was measured. A signal was detected only above the critical temperature and the peak of the response coincided with the resistive transition for both types of films although the correspondence was less exact for the grainy film. The details of the responses and their analysis are presented.

Valco, G. J.↗
NASA NTRS2001

Flame Synthesis of Single- and Multi-Walled Carbon Nanotubes and Nanofibers

Metal-catalyzed carbon nanotubes are highly sought for a diverse range of applications that include nanoelectronics, battery electrode material, catalysis, hydrogen storage media and reinforcing agents in polymer composites. These latter applications will require vast quantities of nanotubes at competitive prices to be economically feasible. Moreover, reinforcing applications may not require ultrahigh purity nanotubes. Indeed, functionalization of nanotubes to facilitate interfacial bonding within composites will naturally introduce defects into the tube walls, lessening their tensile strength. Current methods of aerosol synthesis of carbon nanotubes include laser ablation of composite targets of carbon and catalyst metal within high temperature furnaces and decomposition of a organometallics in hydrocarbons mixtures within a tube furnace. Common to each approach is the generation of particles in the presence of the reactive hydrocarbon species at elevated temperatures. In the laser-ablation approach, the situation is even more dynamic in that particles and nanotubes are borne during the transient cooling phase of the laser-induced plasma for which the temperature far exceeds that of the surrounding hot gases within the furnace process tube. A shared limitation is that more efficient methods of nanoparticle synthesis are not readily incorporated into these approaches. In contrast, combustion can quite naturally create nanomaterials such as carbon black. Flame synthesis is well known for its commercial scalability and energy efficiency. However, flames do present a complex chemical environment with steep gradients in temperature and species concentrations. Moreover, reaction times are limited within buoyant driven flows to tens of milliseconds. Therein microgravity can greatly lessen temperature and spatial gradients while allowing independent control of flame residence times. In preparation for defining the microgravity experiments, the work presented here focuses on the effect of catalyst particle size and reactant gas in 1g.

VanderWal, R. L.↗
DOE OSTI2023

Refined views of ancient ocean chemistry: Tracking trace element incorporation in pyrite framboids using atom probe tomography

The trace element chemistry of pyrite can be used to determine the origin, timing, and conditions of formation of ore deposits; as a vectoring tool for mineral exploration; and to determine the evolution of the Earth’s oceanic and atmospheric chemistry. However, little is known about whether trace elements are held with the pyrite structure or within nano-inclusions of other phases. This distinction is important for two primary reasons. First, trace element incorporation into the pyrite structure can affect the partitioning of other trace elements. Second, if trace elements are held within nano-inclusions, the partition coefficient of the mineral phases that make up the nano-inclusion, rather than pyrite, are the critical consideration in related interpretations. Previous studies addressing this topic have used laser ablation inductively coupled plasma mass spectrometry; however, the resulting data do not provide sufficient spatial resolution to delineate trace element distributions unless the inclusions are large. Further, they use these flat element profiles in time resolved laser ablation output graphs to argue that pyrite trace element content provides a direct relationship between trace element content of seawater and pyrite trace element content. To improve resolution, we have used atom probe tomography to characterize trace element distributions in pyrite framboids from the Cariaco Basin and Demerara Rise in three-dimensions at sub-nanometer resolution. Manganese was found to be concentrated in the pyrite nanocrystal part of the original framboid structure. In contrast, Ni was mostly found along the grain boundary, though it still appeared to be contained within the pyrite structure. Copper was concentrated in later pyrite overgrowths, and As varied in its location. These observations suggest that some important trace elements are incorporated into pyrite during early diagenesis, even in euxinic settings dominated by water-column pyrite formation. Statistical analysis was used to determine whether trace elements were incorporated in the lattice or within nanoscale inclusions (referred to here are nano-inclusions). We found that As, Ni, Cu, and Mn were commonly held within the pyrite structure, but As, Ni, and Cu can also be held as nano-inclusions or within grain interfaces. Incorporation of As is known to enhance the incorporation of other trace elements and in this case appears to correlated to elevated Ni and Cu concentrations in the Cariaco Basin samples. Furthermore, understanding these relationships strongly impacts our ability to utilize pyrite trace metal concentrations to analyze and quantify early ocean chemistry and its evolution through time.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1993

Diamondlike carbon films as protective coatings for superconducting YBa2Cu3O7 films

We have investigated the use of diamondlike carbon (DLC) films for protecting superconducting YBCO films against degradation from exposure to moisture and acid. YBCO thin films on single crystal LaAlO3 and MgO substrates were deposited by laser ablation followed by DLC encapsulation. DLC films were deposited at pressures ranging from high vacuum to 0.1 Torr He. Substrate temperature was varied from 20 to 100 C during the deposition of DLC. The process compatibility of laser ablation was found convenient to sequentially deposit YBCO and DLC films from high purity stoichiometric targets. Epitaxial YBCO films on (100)LaAlO3 and (100)MgO substrates showed identical superconducting transitions before and after encapsulation by a DLC layer. The encapsulated films showed no degradation due to acid treatment or aging over a period of 45 days.

Ganapathi, L.↗
NASA NTRSDate not supplied

Application of High-Spatial Resolution LA-MC-ICP-MS in Planetary Materials

High-precision stable and radiogenic isotopic measurements of planetary materials can help elucidate processes taking place during early Solar System formation, as well as during subsequent planetary differentiation. Laser Ablation Multi Collector Inductively Coupled Plasma Mass Spectrometry (LA-MC-ICP-MS) adds the valuable ability of preserving the spatial context of these isotopic measurements, by sampling small sample volumes (~10 – 60 um diameter) using a pulsed laser system. In the Center for Isotope Cosmochemistry and Geochronology (CICG) at NASA Johnson Space Center, these in-situ isotopic measurements are primarily made using the Applied SpectraTM iX-fs-Tandem LA-LIBS Instrument coupled to the Nu InstrumentsTM SP1700 MC-ICP-MS. The instrumental set-up also provides simultaneous Laser Induced Breakdown Spectroscopy (LIBS) measurements and the potential use of a low energy path with a collision/reaction cell for additional interference removal, though we focus here on the typical high-energy LA-MC-ICP-MS operation. We will provide examples of stable (e.g., Mg) and radiogenic (e.g., Lu-Hf) isotopic systems measured in planetary materials and their terrestrial analogs. The measurement of mass dependent Mg isotopic variations is an important tool for reconstructing processes such as evaporation and condensation of solids in the solar nebula. For early Solar System samples, Mg isotope measurements are also important for the short-lived (t1/2 = 0.7 Ma) Al-Mg chronometer. During laser ablation analyses, the measurement of the Al-Mg isotopic system is made in medium mass resolution (RP ~9500 at ~20% transmission) to limit interferences from 48Ti2+ and 48Ca2+ on 24Mg+, in addition to 52Cr2+ and 12C14N+ on 26Mg+. Measured in the mineral zircon, the 176Lu-176Hf decay system is often used for understanding the growth of continents on Earth, and is also a vital aid in deciphering early large-scale planetary differentiation processes, such as the crystallization of the lunar magma ocean, which is thought to be responsible for much of the Moon’s crust. Lu-Hf measurements are made in low resolution mode (RP <2000), with 10 ion masses (from 171Yb to 180Hf) measured simultaneously to facilitate corrections for isobaric interferences from 176Yb and 176Lu on 176Hf.

Jacob B Setera↗
NASA NTRS2010

Optimizing a Laser Process for Making Carbon Nanotubes

A systematic experimental study has been performed to determine the effects of each of the operating conditions in a double-pulse laser ablation process that is used to produce single-wall carbon nanotubes (SWCNTs). The comprehensive data compiled in this study have been analyzed to recommend conditions for optimizing the process and scaling up the process for mass production. The double-pulse laser ablation process for making SWCNTs was developed by Rice University researchers. Of all currently known nanotube-synthesizing processes (arc and chemical vapor deposition), this process yields the greatest proportion of SWCNTs in the product material. The aforementioned process conditions are important for optimizing the production of SWCNTs and scaling up production. Reports of previous research (mostly at Rice University) toward optimization of process conditions mention effects of oven temperature and briefly mention effects of flow conditions, but no systematic, comprehensive study of the effects of process conditions was done prior to the study described here. This was a parametric study, in which several production runs were carried out, changing one operating condition for each run. The study involved variation of a total of nine parameters: the sequence of the laser pulses, pulse-separation time, laser pulse energy density, buffer gas (helium or nitrogen instead of argon), oven temperature, pressure, flow speed, inner diameter of the flow tube, and flow-tube material.

Arepalli, Sivaram↗
DOE OSTI2022

Single-Cell Metabolomics with Rapid Determination of Chemical Formulas from Isotopic Fine Structures

Metabolomic measurements can provide functional readouts of cellular states and phenotypes. Here, we present a protocol for single-cell metabolomics that permits direct untargeted detection of a broad number of metabolites under ambient conditions, without the need for sample processing, and with high confidence in the discovery and identification of the molecular formulas for detected metabolites. This protocol describes combining fiber-based laser ablation electrospray ionization (f-LAESI) with a 21 Tesla Fourier transform ion cyclotron resonance mass spectrometer (21T-FTICR-MS) to obtain high confidence molecular formula information about detected metabolites. The f-LAESI source utilizes mid-infrared laser ablation through a sharp optical fiber tip, affording direct ambient analysis of cells without the need for sample processing. Using the 21T-FTICR-MS as a mass analyzer enabled measurement of the isotopic fine structure (IFS) for numerous metabolites simultaneously from single cells, and the IFSs were in turn computationally processed to rapidly determine the corresponding elemental compositions. This metabolomics technique complements other single cell omics measurement methods, helping to resolve complex molecular interactions that take place within cells unattainable from single cell transcriptomic and proteomics methods.

mass spectrometry, FTICR, FTMS, ultrahigh mass res↗
DOE OSTI2021

Tools for uranium characterization in carbonate samples: case studies of natural U–Pb geochronology reference materials

Laser ablation U–Pb analyses of carbonate (LAcarb) samples has greatly expanded the potential for U–Pb dating to a variety of carbonate-producing settings. Carbonates that were previously considered impossible to date using isotope dilution methods may preserve radiogenic domains that can be dated using spatially resolved laser ablation geochronology techniques. Work is ongoing to identify reference materials and to consider best practices for LAcarb. In this study we apply standard and emerging characterization tool sets on three natural samples with the dual goal of enhancing the study of carbonates and establishing a new set of well-characterized natural reference materials for LAcarb studies. We start with the existing carbonate reference material WC-1 from the Permian Reef Complex of Texas, building on the published description to offer a deeper look at U and associated trace elements. We consider a tufa sample from the Miocene Barstow Formation of the Mojave Block, California, as a possible secondary calcite reference material due to its well-behaved U–Pb systematics. There are currently no natural dolomite standards. We present an unusual dolomite sample with very well-behaved U–Pb systematics from the Miocene of the Turkana Basin of Kenya as a possible dolomite reference material for LAcarb dating. In addition to using X-ray fluorescence (XRF) mapping and spectroscopy to better understand U in these natural samples, we have analyzed multiple aliquots of each of them for 87 Sr/ 86 Sr by thermal ionization mass spectrometry (TIMS). The Sr isotope compositions are analytically homogeneous within petrographically homogeneous regions of all three samples, and thus these materials could be used as Sr isotope standards as well. While not part of the current contribution, this combination could streamline simultaneous LA analyses of 87 Sr/ 86 Sr and U–Pb geochronology.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Burst-mode dual-comb spectroscopy

We introduce a new modality of dual-comb spectroscopy that enables a simplified and powerful new approach for time-resolved measurements with increased acquisition rates. This "burst mode" form of dual-comb spectroscopy (BM-DCS) relies on the multiplexing of each probe pulse into a short train of pulses. With this approach we demonstrate a time-resolved series of absorption-based spectroscopic measurements of a laser-induced plasma using only a single laser ablation shot and identify 22 Nd lines not previously reported in the literature. The transmission spectra spanned 3.1 THz and were acquired at an effective acquisition rate of 25 kHz with 40 ms time-resolution. This simple modification to 100 MHz level dual-comb systems provides a flexible approach for studying transient and low duty-cycle events such as laser-induced plasmas, combustion, and explosive reactions.

(280.5395) Plasma Diagnostics, broadband laser spe↗
NASA NTRS1989

Patterning of dispenser cathode surfaces to a controlled porosity

A process to pattern slots approximately 1.25 microns in width into 25-micron-thick W films that have been deposited onto flat or concave surfaces is discussed. A 25-micron-thick W film with a high degree of (100) orientation is chemically vapor deposited (CVD) onto a flat or concave Mo mandrel. A 5-micron-thick Al film is deposited onto the CVD W, followed by 2 microns of photoresist. On concave cathodes, XeCl2 laser ablation or X-ray lithography is used to pattern the photoresist, whereas on flat cathodes deep UV lithography can be used. The patterned photoresist serves as the mask in a Cl ion-beam-assisted etching (IBAE) process to pattern the Al. An alternative process is to deposit Al2O3 films onto the W and pattern the Al2O3 using laser ablation. The W film is then patterned to 3-6-micron slot widths using IBAE + ClF3 with the patterned Al or Al2O3 as the mask. Finally, a sputter deposition step is required to close up the slots to approximately 1 micron. The process described is capable of patterning concave dispenser cathodes to a controlled and precise porosity.

Garner, Charles E.↗
NASA NTRS2010

Copoly(imide siloxane) Abhesive Materials with Varied Siloxane Oligomer Length

In this work, low surface energy copoly(imide siloxane)s were synthesized with various siloxane segment lengths. Characterization of these materials revealed that domain formation of the low surface energy component within the matrix was more prevalent for longer siloxane segments as indicated by increased opacity, decreased mechanical properties, and variation of the Tg. Incorporation of siloxanes lowered the polymer s surface energy as indicated by water contact angle values. Topographical modification of these materials by laser ablation patterning further reduced the surface energy, even generating superhydrophobic surfaces. Combined, the contact angle data and particle adhesion testing indicated that copoly(imide siloxane) materials may provide greater mitigation to particulate adhesion than polyimide materials alone. These enhanced surface properties for abhesive applications did result in a reduction of the tensile moduli of the copolymers. It is possible that lower siloxane loading levels would result in retention of the mechanical properties of the polyimide while still affording abhesive surface properties. This hypothesis is currently being investigated. Laser ablation patterning offers further reduction in particle retention as the available surface area for particle adhesion is reduced. Pattern variation and size dependencies are currently being evaluated. For the purposes of lunar dust adhesion mitigation, it is likely that this approach, termed passive due to the lack of input from an external energy source, would not be sufficient to mitigate surface contamination or clean contaminated surfaces for some lunar applications. It is feasible to combine these materials with active mitigation strategies - methods that utilize input from external energy sources - would broaden the applicability of such materials for abhesive purposes. Collaborative efforts along these lines have been initiated with researchers at NASA Kennedy Space Center where experiments are being conducted involving a series of embedded electrodes within polymeric matrices.

Wohl, Christoper J.↗
NASA NTRS2014

Relationship between LIBS Ablation and Pit Volume for Geologic Samples: Applications for in situ Absolute Geochronology

In planetary sciences, in situ absolute geochronology is a scientific and engineering challenge. Currently, the age of the Martian surface can only be determined by crater density counting. However this method has significant uncertainties and needs to be calibrated with absolute ages. We are developing an instrument to acquire in situ absolute geochronology based on the K‐Ar method. The protocol is based on the laser ablation of a rock by hundreds of laser pulses. Laser Induced Breakdown Spectroscopy (LIBS) gives the potassium content of the ablated material and a mass spectrometer (quadrupole or ion trap) measures the quantity of 40Ar released. In order to accurately measure the quantity of released 40Ar in cases where Ar is an atmospheric constituent (e.g., Mars), the sample is first put into a chamber under high vacuum. The 40Arquantity, the concentration of K and the estimation of the ablated mass are the parameters needed to give the age of the rocks. The main uncertainties with this method are directly linked to the measures of the mass (typically some μg) and of the concentration of K by LIBS (up to 10%). Because the ablated mass is small compared to the mass of the sample, and because material is redeposited onto the sample after ablation, it is not possible to directly measure the ablated mass. Our current protocol measures the ablated volume and estimates the sample density to calculate ablated mass. The precision and accuracy of this method may be improved by using knowledge of the sample's geologic properties to predict its response to laser ablation, i.e., understanding whether natural samples have a predictable relationship between laser energy deposited and resultant ablation volume. In contrast to most previous studies of laser ablation, theoretical equations are not highly applicable. The reasons are numerous, but the most important are: a) geologic rocks are complex, polymineralic materials; b) the conditions of ablation are unusual (for example, variable vacuum pressure), and c) the ablation is made with hundreds of successive laser pulses. In this work, we aim to understand the effects that occur on LIBS spectra when a homogeneous rock or a mineral is ablated under high vacuum. Understanding these effects is important to define best practices for LIBS measurements and may lead to improved measurement (or possibly prediction) of the ablated volume. We will describe our laboratory approach and first results, and discuss its utility for situ absolute geochronology campaigns.

Devismes, D.↗