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Action Sheet 36 Final Report

Description: Pursuant to the Arrangement between the European Commission DG Joint Research Centre (EC-JRC) and the Department of Energy (DOE) to continue cooperation on research, development, testing, and evaluation of technology, equipment, and procedures in order to improve nuclear material control, accountancy, verification, physical protection, and advanced containment and surveillance technologies for international safeguards, dated 1 September 2008, the IRMM and LLNL established cooperation in a program on the Study of Chemical Changes in Uranium Oxyfluoride Particles under IRMM-LLNL Action Sheet 36. The work under this action sheet had 2 objectives: (1) Achieve a better understanding of the loss of fluorine in UO{sub 2}F{sub 2} particles after exposure to certain environmental conditions; and (2) Provide feedback to the EC-JRC on sample reproducibility and characteristics.
Date: February 24, 2012
Creator: Kips, R. E.; Kristo, M. J. & Hutcheon, I. D.
Partner: UNT Libraries Government Documents Department

Nuclear Forensics and Attribution for Improved Energy Security: The Use of Taggants in Nuclear Fuel

Description: The Global Nuclear Energy Partnership (GNEP), recently announced by DOE Secretary Bodman, poses significant new challenges with regard to securing, safeguarding, monitoring and tracking nuclear materials. In order to reduce the risk of nuclear proliferation, new technologies must be developed to reduce the risk that nuclear material can be diverted from its intended use. Regardless of the specific nature of the fuel cycle, nuclear forensics and attribution will play key roles to ensure the effectiveness of nonproliferation controls and to deter the likelihood of illicit activities. As the leader of the DHS nuclear and radiological pre-detonation attribution program, LLNL is uniquely positioned to play a national leadership role in this effort. Ensuring that individuals or organizations engaged in illicit trafficking are rapidly identified and apprehended following theft or diversion of nuclear material provides a strong deterrent against unlawful activities. Key to establishing this deterrent is developing the ability to rapidly and accurately determine the identity, source and prior use history of any interdicted nuclear material. Taggants offer one potentially effective means for positively identifying lost or stolen nuclear fuels. Taggants are materials that can be encoded with a unique signature and introduced into nuclear fuel during fuel fabrication. During a nuclear forensics investigation, the taggant signature can be recovered and the nuclear material identified through comparison with information stored in an appropriate database. Unlike serial numbers or barcodes, microtaggants can provide positive identification with only partial recovery, providing extreme resistance to any attempt to delete or alter them.
Date: April 5, 2007
Creator: Kristo, M J; Robel, M & Hutcheon, I D
Partner: UNT Libraries Government Documents Department

Chemical imaging of biological materials by NanoSIMS using isotopic and elemental labels

Description: The NanoSIMS 50 combines unprecedented spatial resolution (as good as 50 nm) with ultra-high sensitivity (minimum detection limit of {approx}200 atoms). The NanoSIMS 50 incorporates an array of detectors, enabling simultaneous collection of 5 species originating from the same sputtered volume of a sample. The primary ion beam (Cs{sup +} or O{sup -}) can be scanned across the sample to produce quantitative secondary ion images. This capability for multiple isotope imaging with high spatial resolution provides a novel new approach to the study of biological materials. Studies can be made of sub-regions of tissues, mammalian cells, and bacteria. Major, minor and trace element distributions can be mapped on a submicron scale, growth and metabolism can be tracked using stable isotope labels, and biogenic origin can be determined based on composition. We have applied this technique extensively to mammalian and prokaryotic cells and bacterial spores. The NanoSIMS technology enables the researcher to interrogate the fate of molecules of interest within cells and organs through elemental and isotopic labeling. Biological applications at LLNL will be discussed.
Date: April 10, 2006
Creator: Weber, P K; Fallon, S J; Pett-Ridge, J; Ghosal, S & Hutcheon, I D
Partner: UNT Libraries Government Documents Department

Bioforensics: Characterization of biological weapons agents by NanoSIMS

Description: The anthrax attacks of Fall 2001 highlight the need to develop forensic methods based on multiple identifiers to determine the origin of biological weapons agents. Genetic typing methods (i.e., DNA and RNA-based) provide one attribution technology, but genetic information alone is not usually sufficient to determine the provenance of the material. Non-genetic identifiers, including elemental and isotopic signatures, provide complementary information that can be used to identify the means, geographic location and date of production. Under LDRD funding, we have successfully developed the techniques necessary to perform bioforensic characterization with the NanoSIMS at the individual spore level. We have developed methods for elemental and isotopic characterization at the single spore scale. We have developed methods for analyzing spore sections to map elemental abundance within spores. We have developed rapid focused ion beam (FIB) sectioning techniques for spores to preserve elemental and structural integrity. And we have developed a high-resolution depth profiling method to characterize the elemental distribution in individual spores without sectioning. We used these newly developed methods to study the controls on elemental abundances in spores, characterize the elemental distribution of in spores, and to study elemental uptake by spores. Our work under this LDRD project attracted FBI and DHS funding for applied purposes.
Date: February 26, 2007
Creator: Weber, P K; Ghosal, S; Leighton, T J; Wheeler, K E & Hutcheon, I D
Partner: UNT Libraries Government Documents Department

Towards consistent chronology in the early Solar System: high resolution 53Mn-53Cr chronometry for chondrules.

Description: New high-precision {sup 53}Mn-{sup 53}Cr data obtained for chondrules extracted from a primitive ordinary chondrite, Chainpur (LL3.4), define an initial {sup 53}Mn/{sup 55}Mn ratio of (5.1 {+-} 1.6) x 10{sup -6}. As a result of this downward revision from an earlier higher value of (9.4 {+-} 1.7) x 10{sup -6} for the same meteorite (Nyquist et al. 2001), together with an assessment of recent literature, we show that a consistent chronology with other chronometers such as the {sup 26}Al-{sup 26}Mg and {sup 207}Pb-{sup 206}Pb systems emerges in the early Solar System.
Date: May 2, 2007
Creator: Yin, Q; Jacobsen, B; Moynier, F & Hutcheon, I D
Partner: UNT Libraries Government Documents Department

Constraints on the Origin of Chondrules and CAIs from Short-Lived and Long-Lived Radionuclides

Description: The high time resolution Pb-Pb ages and short-lived nuclide based relative ages for CAIs and chondrules are reviewed. The solar system started at 4567.2 {+-} 0.6Ma inferred from the high precision Pb-Pb ages of CAIs. Time scales of CAIs ({le}0.1Myr), chondrules (1-3Myr), and early asteroidal differentiation ({ge}3Myr) inferred from {sup 26}Al relative ages are comparable to the time scale estimated from astronomical observations of young star; proto star, classical T Tauri star and week-lined T Tauri star, respectively. Pb-Pb ages of chondrules also indicate chondrule formation occur within 1-3 Myr after CAIs. Mn-Cr isochron ages of chondrules are similar to or within 2 Myr after CAI formation. Chondrules from different classes of chondrites show the same range of {sup 26}Al ages in spite of their different oxygen isotopes, indicating that chondrule formed in the localized environment. The {sup 26}Al ages of chondrules in each chondrite class show a hint of correlation with their chemical compositions, which implies the process of elemental fractionation during chondrule formation events.
Date: October 24, 2005
Creator: Kita, N. T.; Huss, G. R.; Tachibana, S.; Amelin, Y.; Nyquist, L. E. & Hutcheon, I. D.
Partner: UNT Libraries Government Documents Department

High resolution trace element and isotopic imaging of microbial systems by NanoSIMS

Description: The NanoSIMS 50 is the state of the art in high spatial resolution secondary ion mass spectrometry (SIMS), combining unprecedented spatial resolution (as good as 50 nm) with ultra-high sensitivity (minimum detection limit of {approx}200 atoms). The NanoSIMS has an array of detectors, enabling simultaneous collection of 5 species originating from the same sputtered volume of a sample. The primary ion beam (Cs{sup +} or O{sup -}) can be scanned across the sample to produce quantitative secondary ion images. This capability provides a novel new approach to the study of microbial systems. We have applied our NanoSIMS to various microbial systems. We have analyzed sub-regions of bacterial cells, biofilms, and other associated materials to map trace element and isotopic ratios on a submicron scale. Growth and metabolism have been tracked using stable isotope labels. High resolution SIMS is particularly powerful when used in combination with other high resolution techniques, such as FIB and TEM. Examples will be presented to demonstrate the range of capabilities of this technique for microbial systems.
Date: September 8, 2005
Creator: Weber, P K; Fallon, S J; Pett-Ridge, J; Ghosal, S; Ramon, C E & Hutcheon, I D
Partner: UNT Libraries Government Documents Department

Membrane composition analysis by imaging mass spectrometry

Description: Membranes on solid supports offer an ideal format for imaging. Secondary ion mass spectrometry (SIMS) can be used to obtain composition information on membrane-associated components. Using the NanoSIMS50, images of composition variations in membrane domains can be obtained with a lateral resolution better than 100 nm. By suitable calibration, these variations in composition can be translated into a quantitative analysis of the membrane composition. Progress towards imaging small phase-separated lipid domains, membrane-associated proteins and natural biological membranes will be described.
Date: March 29, 2006
Creator: Boxer, S G; Kraft, M L; Longo, M; Hutcheon, I D & Weber, P K
Partner: UNT Libraries Government Documents Department

Renewed Search for FUN (Fractionated and Unidentified Nuclear Effects) in Primitive Chondrites

Description: Ca-Al-rich inclusions (CAIs) found in primitive chondrites record processes and conditions of the earliest solar system as they are the oldest known solid objects formed in the solar system [1,2]. CAIs with fractionation and unidentified nuclear anomalies (FUN CAIs; [3]) are very rare and thusfar found exclusively in CV carbonaceous chondrites (e.g., Allende and Vigarano)[4]. FUN CAIs are characterized by large nucleosynthetic anomalies in several elements (Ca, Ti, Si, Sr, Ba, Nd, and Sm), large mass-dependant isotope fractionation (Mg, Si, and O), and very little initial {sup 26}Al [4,5 and reference therein]. Formation of FUN CAIs by thermal processing of presolar dust aggregates prior to the injection of {sup 26}Al into the protoplanetary disk has been proposed. More recently [5] proposed that FUN CAIs formed from a protosolar molecular cloud after injection of {sup 26}Al but before {sup 26}Al and {sup 27}Al were completely homogenized. Therefore discovering more FUN CAIs to perform U-Pb and other short-lived chronometric dating will provide key constraints on the age of the solar system, the isotopic composition of the protosolar molecular cloud, the earliest stages of the thermal processing in the solar system and the timing of {sup 26}Al and other short-lived radionuclide injection into the nascent solar system. Most known FUN CAIs were discovered and studied > 30 yr ago, and their isotope ratios determined using thermal ionization mass spectrometry (TIMS). Most of these FUN CAIs were almost or entirely consumed during their respective analyses. [5] recently identified a new FUN CAI (NWA 779 KS-1) based on O and Mg isotope ratios determined by SIMS and MCICPMS, respectively. We have initiated a systematic search for FUN CAIs in primitive chondrites, taking advantage of the large mass-dependant Mg isotope effects known for FUN inclusions with little or no inferred {sup 26}Al. Our strategy is to ...
Date: April 7, 2011
Creator: Tollstrup, D L; Wimpenny, J B; Yin, Q -; Ebel, D S; Jacobsen, B & Hutcheon, I D
Partner: UNT Libraries Government Documents Department

Chemical Imaging of Lipid Domains by High-Resolution Secondary Ion Mass Spectrometry

Description: Lipid microdomains within supported lipid bilayers composed of binary phosphocholine mixtures were chemically imaged by high-resolution secondary ion mass spectrometry performed with the NanoSIMS 50 (Cameca Instruments). This instrument images the sample components based on the elemental or isotopic composition of their atomic and small molecular secondary ions. Up to five different secondary ions can be simultaneously detected, and a lateral resolution of 50 nm can be achieved with high sensitivity at high mass resolution. In our experiments, the NanoSIMS 50 extensively fragmented the supported membrane, therefore an isotopic labeling strategy was used to encode the identities of the lipid components. Supported lipid membranes that contained distinct lipid microdomains were freeze-dried to preserve their lateral organization and analyzed with the NanoSIMS 50. Lipid microdomains as small as 100 nm in diameter were successfully imaged, and this was validated by comparison to AFM images taken at the same region prior to chemical imaging. Quantitative information on the lipid distribution within the domain was also determined by calibrating against supported membranes of known composition. We believe this will be a valuable approach for analyzing the composition of complex membrane domains with high spatial resolution.
Date: September 30, 2005
Creator: Kraft, M L; Weber, P K; Longo, M L; Hutcheon, I D & Boxer, S G
Partner: UNT Libraries Government Documents Department

Formation of spinel-, hibonite-rich inclusions found in CM2 carbonaceous chrondrites

Description: We report petrography, mineral chemistry, bulk chemistry, and bulk isotopic compositions of a suite of 40 spinel-rich inclusions from the Murchison (CM2) carbonaceous chondrite. Seven types of inclusions are identified based on mineralogy: spinel-hibonite-perovskite; spinel-perovskite-pyroxene; spinel-perovskite-melilite; spinel-hibonite-perovskite-melilite; spinel-hibonite; spinel-pyroxene; and spinel-melilite-anorthite. Hibonite-bearing inclusions have Ti-poor spinel compared to the hibonite-free ones, and spinel-hibonite-perovskite inclusions have the highest average bulk TiO{sub 2} contents (7.8 wt%). The bulk CaO/Al{sub 2}O{sub 3} ratios of the inclusions range from 0.005-0.21, well below the solar value of 0.79. Hibonite-, spinel-rich inclusions consist of phases that are not predicted by condensation calculations to coexist; in the equilibrium sequence, hibonite is followed by melilite, which is followed by spinel. Therefore, hibonite-melilite or melilite-spinel inclusions should be dominant instead. One explanation for the 'missing melilite' is that it condensed as expected but was lost due to evaporation of Mg and Ca during heating and melting of spherule precursors. If this theory were correct, melilite-poor spherules would have isotopically heavy Mg and Ca. Except for one inclusion with F{sub Mg} = 4.3 {+-} 2.6{per_thousand}/amu and another with isotopically light Ca (F{sub Ca} = 3.4 {+-} 2.0{per_thousand}/amu), however, all the inclusions we analyzed have normal isotopic compositions within their 2{sigma} uncertainties. Thus, we found no evidence for significant mass-dependent fractionation. Our preferred explanation for the general lack of melilite among hibonite-, spinel-bearing inclusions is kinetic inhibition of melilite condensation relative to spinel. Because of similarities between the crystal structures of hibonite and spinel, it should be easier for spinel to form from hibonite than for melilite to do so.
Date: November 3, 2005
Creator: Simon, S B; Grossman, L; Hutcheon, I D; Phinney, D L; Weber, P K & Fallon, S J
Partner: UNT Libraries Government Documents Department

Chemical Imaging of the Cell Membrane by NanoSIMS

Description: The existence of lipid microdomains and their role in cell membrane organization are currently topics of great interest and controversy. The cell membrane is composed of a lipid bilayer with embedded proteins that can flow along the two-dimensional surface defined by the membrane. Microdomains, known as lipid rafts, are believed to play a central role in organizing this fluid system, enabling the cell membrane to carry out essential cellular processes, including protein recruitment and signal transduction. Lipid rafts are also implicated in cell invasion by pathogens, as in the case of the HIV. Therefore, understanding the role of lipid rafts in cell membrane organization not only has broad scientific implications, but also has practical implications for medical therapies. One of the major limitations on lipid organization research has been the inability to directly analyze lipid composition without introducing artifacts and at the relevant length-scales of tens to hundreds of nanometers. Fluorescence microscopy is widely used due to its sensitivity and specificity to the labeled species, but only the labeled components can be observed, fluorophores can alter the behavior of the lipids they label, and the length scales relevant to imaging cell membrane domains are between that probed by fluorescence resonance energy transfer (FRET) imaging (<10 nm) and the diffraction limit of light. Topographical features can be imaged on this length scale by atomic force microscopy (AFM), but the chemical composition of the observed structures cannot be determined. Immuno-labeling can be used to study the distribution of membrane proteins at high resolution, but not lipid composition. We are using imaging mass spectrometry by secondary ion mass spectrometry (SIMS) in concert with other high resolution imaging methods to overcome these limitations. The experimental approach of this project is to combine molecule-specific stable isotope labeling with high-resolution SIMS using a Cameca NanoSIMS 50 ...
Date: February 23, 2010
Creator: Weber, P K; Kraft, M L; Frisz, J F; Carpenter, K J & Hutcheon, I D
Partner: UNT Libraries Government Documents Department

Subsurface damage assessment with atomic force microscopy

Description: The performance of transparent optics in high fluence applications is often dominated by inhomogeneities in the first few hundred nanometers of material. Defects undetectable with optical methods can cause catastrophic failures when used in critical applications where high strength, chemical or mechanical resistance or extreme smoothness is required. Not only are these defects substantially smaller than the wavelength of visible light, they are often concealed below a layer of glass-like material deposited during the polishing process. In high quality glass, the chemical and material properties of the outermost layer are modified by the grinding, lapping and polishing processes used in fabrication. Each succeeding step in a process is designed to remote damage from the previous operation. However, any force against the surface, no matter how slight will leave evidence of this damage. These processes invariably create dislocations, cracks and plastic deformation in the subsurface region.
Date: April 16, 1999
Creator: Carr, J W; Fearon, E; Hutcheon, I D & Summers, L J
Partner: UNT Libraries Government Documents Department