55 Matching Results

Search Results

Advanced search parameters have been applied.
in subjects: "Mass Spectroscopy"  
Results: 1 - 24 next
open access

Mass Spectrometric Fingerprinting of Tank Waste Using Tunable, Ultrafast Infrared Lasers

Description: During the past year, we have initiated systematic studies of mass spectrometry of model tank-waste materials using both conventional nanosecond, single-frequency and tunable, subpicosecond mid-infrared lasers. In addition to making initial measurements, we have also constructed several new items of equipment for the experiment and begun to develop a model of the processes which lead to efficient desorption and ionization of organic molecules (e.g., toluene, benzene, crown ethers) from sodium n… more
Date: June 1, 1999
Creator: Haglund, Richard F., Jr. & Hess, Wayne P.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Hydrologic and Geochemical Controls on the Transport of Radionuclides in Natural Undisturbed Arid Environments as Determined by Accelerator Mass Spectrometry Measurements

Description: This project developed low-level analytical methods for the measurement of radionuclides by accelerator mass spectrometry. The contaminant radionuclides potentially measurable by AMS include: 14C, 36Cl, 59Ni, 63Ni, 90Sr, 93Zr, 99Tc, 129I, 239Np, 239Pu, and other actinides. We chose to concentrate on 36Cl, 99Tc, 90Sr, and 129I. These nuclides were globally distributed as fallout during the era of atmospheric nuclear testing, and occur today in almost every environment. They also are prominent co… more
Date: December 31, 1999
Creator: Nimz, Gregory J.; Caffee, Marc W. & McAninch, Jeffrey
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Thermospray Mass Spectrometry Ionization Processes Fundamental Mechanisms for Speciation, Separation and Characterization of Organic complexants in DOE Wastes

Description: The overall objective is to develop and enhance our understanding of chemical equilibria for major organic complexant species (chelators, chelator fragments, small organic acids and their products) in multi-component aqueous matrices such as the mixtures of DOE stored wastes. To progress toward this objective, organic complexants must be separated and speciated in mixtures of high ionic strength. HPLC employing zirconia-based stationary phases is being studied in order to understand the separat… more
Date: June 1, 1999
Creator: Caton, John E.; Bostick, Debra T.; Carr, Peter W. & Mabbott, Gary
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Monitoring Genetic & Metabolic Potential for In Situ Bioremediation: Mass Spectrometry

Description: A number of DOE sites are contaminated with dense non-aqueous phase liquids (DNAPLs) such as carbon tetrachloride and trichloroethylene. At many of these sites, microbial bioremediation is an attractive strategy for cleanup, since it has the potential to degrade DNAPLs in situ. A rapid screening method to determine the broad range potential of a site's microbial population for contaminant degradation would greatly facilitate assessment for in situ bioremediation, as well as for monitoring ongoi… more
Date: June 1, 1999
Creator: Buchanan, Michelle V.; Hurst, Gregory B.; Lidstrom, Mary E.; Auman, Anne; Britt, Phillip F.; Costello, Andria et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Particle Generation by Laser Ablation in Support of Chemical Analysis of High Level Mixed Waste from Plutonium Production Operations

Description: To provide fundamental mechanistic studies of laser-produced particulate formation in support of the analysis of radioactive and/or toxic materials by Laser Assisted-Inductively Coupled Plasma Mass Spectroscopy (LA-ICP-MS).
Date: June 1, 1999
Creator: Dickinson, J. Thomas
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Chemical Speciation of Strontium, Americium, and Curium in High Level Waste: Predictive Modeling of Phase Partitioning During Tank Processing

Description: In this research program, Pacific Northwest National Laboratory (PNNL) and Florida State University (FSU) are investigating the speciation of strontium and americium/curium in the presence of selected organic chelating agents (ethylenediaminetetraacetic acid (EDTA), N-(2-hydroxyethyl) aethylenediaminetriacetic acid (HEDTA), nitrilotriacetic acid (NTA), and iminodiacetic acid (IDA)) over ranges of hydroxide, carbonate, ionic strength, and competing metal ion concentrations present in high-level … more
Date: June 1, 1999
Creator: Felmy, Andrew R.; Choppin, Gregory; Dixon, David A. & Campbell, James A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Improved Performance of the Alkaline-Side CSEX Process for Cesium Extraction from Alkaline High-Level Waste Obtained by Characterization of the Effect of Surfactant Impurities

Description: Improved understanding and performance of the alkaline-side CSEX process has been obtained through the characterization of impurity effects that hinder complete stripping of cesium from the solvent. It is shown in this report that tests of the alkaline-side CSEX process conducted in the summer and fall of 1998 were complicated by the presence of common surfactant anions, undecyl- and dodecylsulfonate, as trace impurities in the two simulants tested. This conclusion was drawn from the results of… more
Date: November 4, 1999
Creator: Delmau, L. H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Fundamental chemistry, Characterization, and Separation of Technetium Complexes in Hanford Waste

Description: The ultimate goal of this proposal is to separate technetium from Hanford tank waste. Our recent work has shown that a large portion of the technetium is not pertechnetate (TcO4-) and is not easily oxidized. This has serious repercussions for technetium partitioning schemes because they are designed to separate this chemical form. Rational attempts to oxidize these species to TcO4- for processing or to separate the nonpertechnetate species themselves would be facilitated by knowing the identity… more
Date: June 1999
Creator: Schroeder, Norman C.; Blanchard, David L., Jr. & Ashley, Kenneth R.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Improved Analytical Characterization of Solid Wastes-Forms by Fundamental Development of Laser Ablation Technology

Description: Laser ablation (LA) with inductively coupled plasma mass spectrometry (ICP-MS) has been demonstrated as a viable technology for sample characterization within the EM complex. Laser ablation systems have been set up at the Hanford Site, Savannah River Plant, the Pu immobilization program (MD), Los Alamos, and at numerous other DOE facilities. Advancement of this technology is warranted to guarantee accuracy of analysis for the diversity of complex EM samples. This EMSP research endeavors to unde… more
Date: June 1, 1999
Creator: Russo, Richard E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Ion-Source Modeling and Improved Performance of the CAMS High-Intensity Cs-Sputter Ion Source

Description: The interior of the high-intensity Cs-sputter source used in routine operations at the Center for Accelerator Mass Spectrometry (CAMS) has been computer modeled using the program NEDLab, with the aim of improving negative ion output. Space charge effects on ion trajectories within the source were modeled through a successive iteration process involving the calculation of ion trajectories through Poisson-equation-determined electric fields, followed by calculation of modified electric fields inc… more
Date: October 22, 1999
Creator: Brown, T. A.; Roberts, M. L. & Southon, J. R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Model Calculations of Continuous-Wave Laser Ionization of Krypton

Description: This report describes modeling of a scheme that uses continuous-wave (CW) lasers to ionize selected isotopes of krypton with high isotopic selectivity. The models predict that combining this ionization scheme with mass spectrometric measurement of the resulting ions can be the basis for ultra-sensitive methods to measure {sup 85}Kr in the presence of a 10{sup 11} excess of the stable krypton isotopes. Two experimental setups are considered in this model: the first setup is for krypton as a stat… more
Date: July 27, 1999
Creator: Cannon, Bret D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Human folate metabolism using 14C-accelerator mass spectrometry

Description: Folate is a water soluble vitamin required for optimal health, growth and development. It occurs naturally in various states of oxidation of the pteridine ring and with varying lengths to its glutamate chain. Folates function as one-carbon donors through methyl transferase catalyzed reactions. Low-folate diets, especially by those with suboptimal methyltransferase activity, are associated with increased risk of neural tube birth defects in children, hyperhomocysteinemic heart disease, and cance… more
Date: March 25, 1999
Creator: Arjomand, A; Bucholz, B A; Clifford, A J; Duecker, S R; Johnson, H; Schneider, P D et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Material accountancy measurement techniques in dry-powdered processing of nuclear spent fuels.

Description: The paper addresses the development of inductively coupled plasma-mass spectrometry (ICPMS), thermal ionization-mass spectrometry (TIMS), alpha-spectrometry, and gamma spectrometry techniques for in-line analysis of highly irradiated (18 to 64 GWD/T) PWR spent fuels in a dry-powdered processing cycle. The dry-powdered technique for direct elemental and isotopic accountancy assay measurements was implemented without the need for separation of the plutonium, uranium and fission product elements i… more
Date: March 24, 1999
Creator: Wolf, S. F.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

{sup 129}I Interlaboratory comparison: phase I and phase II

Description: An interlaboratory comparison exercise for {sup 129}I was organized and conducted. Nine laboratories participated in the exercise to either a full or limited extent. In Phase I of the comparison, 11 samples were measured. The suite of samples contained both synthetic ''standard type'' materials (i.e., AgI) and environmental materials. The isotopic {sup 129}I/{sup 127}I ratios of the samples varied from 10{sup {minus}8} to 10{sup {minus}14}. In this phase, each laboratory was responsible for its… more
Date: September 30, 1999
Creator: Caffee, M W & Roberts, M L
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Tips and Traps in the 14c Bio-AMS Preparation Laboratory (WSam 7)

Description: Maintaining a contamination free sample preparation lab for biological 14 C AMS requires the same or more diligence as a radiocarbon dating prep lab. Isotope ratios of materials routinely range over 4-8 orders of magnitude in a single experiment, dosing solutions contain thousands of DPM and gels used to separate proteins possess 14 C ratios of 1pMC. Radiocarbon contamination is a legacy of earlier tracer work in most biological laboratories, even if they were never hot labs. Removable surface … more
Date: October 12, 1999
Creator: Buchholz, B. A.; Haack, K. W.; Stewart, P. H. & Vogel, J. S.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

A compact tritium AMS system

Description: Tritium ({sup 3}H) is a radioisotope that is extensively utilized in biological and environmental research. For biological research, {sup 3}H is generally quantified by liquid scintillation counting requiring gram-sized samples and counting times of several hours. For environmental research, {sup 3}H is usually quantified by {sup 3}He in-growth which requires gram-sized samples and in-growth times of several months. In contrast, provisional studies at LLNL's Center for Accelerator Mass Spectrom… more
Date: September 23, 1999
Creator: Chiarappa, M L; Dingley, K H; Hamm, R W; Love, A H & Roberts, M L
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Measurement of plutonium and other actinide elements at the center for accelerator mass spectrometry: a comparative assessments of competing techniques

Description: Low-level measurements of the long-lived actinide isotopes have a number of important applications throughout the DOE complex. These include radiobioassay programs, environmental assessments, characterization of radioactive wastes, evaluation of waste storage and treatment options, environmental remediation, basic research in chemistry and geochemistry, and other specialized non- proliferation and national security applications. As an example, it has been estimated that for the next few decades… more
Date: February 1, 1999
Creator: Hamilton, T. F. & McAninch, J. E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

AMS measurements of actinides and technetium at LLNL

Description: The Center for Accelerator Mass Spectrometry (CAMS) and the Health and Ecological Assessment Division (HEA) at Lawrence Livermore National Laboratory (LLNL) are developing methods for the measurement of technetium and plutonium as part of a long-term effort to expand our accelerator mass spectrometry (AMS) capabilities to isotopes throughout the periodic table. AMS provides ultratrace sensitivity for these nuclides with high rejection of interferences and low susceptibility to matrix components… more
Date: September 1, 1999
Creator: McAninch, J. E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Novel Mass Spectrometry Mutation screening for contaminant Impact Analysis

Description: The objective of this program is to develop innovative mass spectrometry technology to achieve fast mutation screening and to reveal the linkage between gene mutation and contaminants. Mass spectrometry has the potential to achieve very fast speed sample analysis. However, the poor mass resolution and low detection efficiency for long DNAs limit the broad application for mutation analysis. New innovative approaches for improving mass resolution and detection sensitivity will be pursued to help … more
Date: June 1, 1999
Creator: Chen, Chung Hsuan (Winston)
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

High Temperature Condensed Phase Mass Spectrometric Analysis

Description: This program (in the 20th month as of this writing) was initiated with the goal of designing, constructing and operating a materials analysis instrument capable of obtaining a wide variety of chemical measurements on a material at high temperature. This instrument is being built around a quadrupole mass spectrometer. There are three main modes of obtaining spectra from the high temperature condensed phase material; surface ionization from the condensed phase, secondary ion mass spectrometry (SI… more
Date: June 1, 1999
Creator: Delmore, James E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
Back to Top of Screen