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Resonant laser ablation ion trap mass spectrometry -- Recent applications for chemical analysis

Description: Resonant Laser Ablation (RLA) is a useful ionization process for selectively producing gas phase ions from a solid sample. Recent use of RLA for mass spectrometry by this group and by others has produced a wealth of knowledge and useful analytical techniques. The method relies upon the focusing of modest intensity laser pulses ({le} 10{sup 7} W {center_dot} Cm{sup {minus}2}) upon a sample surface. A small quantity of material is vaporized, and atoms of desired analyte are subsequently ionized by (n + m) photon processes in the gas phase (where n = number of photons to a resonant transition and m = number of photons to exceed the ionization limit). The authors have been using (2 + 1) resonant ionization schemes for this work. Quadrupole ion trap mass spectrometry is realizing a very prominent role in current mass spectrometric research. Ion traps are versatile, powerful and extremely sensitive mass spectrometers, capable of a variety of ionization modes, MS{sup n} type experiments, high mass ranges and high resolution, all for a fraction of the cost of other instrumentation with similar capabilities. Quadrupole ion traps are ideally suited to pulsed ionization sources such as laser ionization methods, since their normal operational method (Mass Selective Instability) relies upon the storage of ions from a finite ionization period followed by ejection and detection of these ions based upon their mass to charge ratios. The paper describes selective ionization for trace atomic analysis, selective reagent ion source for ion chemistry investigations, and the analysis of ``difficult`` environmental contaminants, i.e., TBP.
Date: December 31, 1995
Creator: Gill, C.G.; Garrett, A.W.; Hemberger, P.H. & Nogar, N.S.
Partner: UNT Libraries Government Documents Department

Methods for the rapid detection of biological and chemical weapons

Description: This is the final report of a one-year, Laboratory-Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). This work undertook the development of technology for the detection of chemical and biological agents. The project consisted of three tasks: (1) modifying a transportable mass spectrometer for the detection of chemical gents; (2) demonstrating the detection of a specific bacterial DNA sequence using a fluorescence-based single- copy gene detector; and (3) upgrading a surface acoustic wave measurement station.
Date: August 1, 1997
Creator: Castro, A.; Hemberger, P.H. & Swanson, B.I.
Partner: UNT Libraries Government Documents Department

Real-time broad spectrum characterization of hazardous waste by membrane introduction mass spectrometry. 1998 annual progress report

Description: 'As of May 1, 1998, the authors have designed and tested the rare gas ionization source and the associated ion optics. Ions are generated in a microwave plasma which can be supported by helium or argon from room air. A series of extraction and focusing lenses followed by a linear quadrupole serves to inject ions into the ion trap. Injection efficiency and favorable trapping of externally-generated ions are dependent on several parameters including lens potentials, quadrupole operation, buffer gas pressure, kinetic energy of the injected ions, and amplitude of the trapping potential. They have investigated rf-only operation of the linear quadrupole. RF/DC operation will be studied as a means for further reducing interferences. A publication on this work has been submitted to Int. J. Mass. Spectrom. Ion Proc. To date they have used MIMS to detect 40 volatile and SVOCs without preconcentration, primarily from an air matrix. The 40 analytes range in boiling point from 21 to 279 C and include chlorinated and oxygenated solvents, chlorophenols, polyaromatic hydrocarbons, and substituted benzenes. Using MIMS, they have demonstrated the direct, simultaneous detection of a volatile organic compound, a semi-volatile organic compound, and an organometallic compound with a single analytical technique in near real-time for two waste streams, air and water. To their knowledge, this is the first time this has been accomplished. They have investigated the analysis of several organometallic compounds containing heavy metals by MIMS. These include lead and tin compounds. When these molecules are analyzed, organic fragment ions are observed. However, neither the intact molecular ion, nor the metal ion species are seen in the mass spectrum. These results are interesting because in the spectra of metal compounds most of the ion current is normally carried by metal-containing species [J. Charalambous, ed., Mass Spectrometry of Metal Compounds]. The authors speculate ...
Date: June 1, 1998
Creator: Hemberger, P.H. & Cisper, M.
Partner: UNT Libraries Government Documents Department

A transportable turnkey gas chromatograph/ion trap detector for field analysis of environmental samples

Description: We have developed two transportable gas chromatograph/ion trap detectors (GC/ITD) for the in-situ characterization of chemical waste sites. These instruments are based on a modular design and can be readily modified in the field for air, water, or soil sampling. A purge-and-trap GC is used for the separation of volatile organic compounds before their introduction to the ion trap for mass spectral analysis. A secondary, or daughter, microprocessor controls ancillary hardware by means of the ion trap software. Most analyses are accomplished in an automated 20-min procedure. The detection limit for trichloroethylene in water is in the low part-per-trillion range. The analysis of soil and water samples is demonstrated by using surrogate samples spiked with 24 volatile organic compounds. The first instrument has been used under field conditions for soil analysis at a chemical waste site. The second-generation instrument differs from the first in the extensive use of commercially available equipment. The second-generation instrument will be briefly described here and some preliminary comparisons will be made to the first instrument. 11 refs., 8 figs., 2 tabs.
Date: January 1, 1990
Creator: Cisper, M.E.; Alarid, J.E.; Hemberger, P.H. & Vanderveer, E.P.
Partner: UNT Libraries Government Documents Department

Capability of environmental sampling to detect undeclared cask openings

Description: The goal of this study is to determine the signatures that would allow monitors to detect diversion of nuclear fuel (by a diverter) from a storage area such as a geological repository. Due to the complexity of operations surrounding disposal of spent nuclear fuel in a geologic repository, there are several places that a diversion of fuel could take place. After the canister that contains the fuel rods is breached, the diverter would require a hot cell to process or repackage the fuel. A reference repository and possible diversion scenarios are discussed. When a canister is breached, or during reprocessing to extract nuclear weapons material (primarily Pu), several important isotopes or signatures including tritium, {sup 85}Kr, and {sup 129}I are released to the surrounding environment and have the potential for analysis. Estimates of release concentrations of the key signatures from the repository under a hypothetical diversion scenario are presented and discussed. Gas analysis data collected from above-ground storage casks at Idaho National Engineering and Environmental Laboratory (INEEL) Test Area North (TAN) are included and discussed in the report. In addition, LANL participated in gas sampling of one TAN cask, the Castor V/21, in July 1997. Results of xenon analysis from the cask gas sample are presented and discussed. The importance of global fallout and recent commercial reprocessing activities and their effects on repository monitoring are discussed. Monitoring and instrumental equipment for analysis of the key signature isotopes are discussed along with limits of detection. A key factor in determining if diversion activities are in progress at a repository is the timeliness of detection and analysis of the signatures. Once a clandestine operation is suspected, analytical data should be collected as quickly as possible to support any evidence of diversion.
Date: December 1, 1997
Creator: Beckstead, L.W.; Efurd, D.W.; Hemberger, P.H.; Abhold, M.E. & Eccleston, G.W.
Partner: UNT Libraries Government Documents Department

Resonant laser ablation: mechanisms and applications

Description: We report on aspects of resonant laser ablation (RLA) behavior for a number of sample types: metals, alloys, thin films, zeolites and soil. The versatility of RLA is demonstrated, with results on a variety of samples and in several mass spectrometers. In addition, the application to depth profiling of thin films is described; absolute removal rates and detection limits are also displayed. A discussion of possible mechanisms for low-power ablation is presented.
Date: October 1, 1996
Creator: Anderson, J.E.; Allen, T.M.; Garrett, A.W.; Gill, C.G.; Hemberger, P.H.; Kelly, P.B. et al.
Partner: UNT Libraries Government Documents Department

Resonant laser ablation: Applications and mechanistic aspects

Description: Ever since the first report of laser action, it has been recognized that laser ablation (evaporation/volatilization) may provide a useful sampling mechanism for chemical analysis. In particular, laser ablation is rapidly gaining popularity as a method of sample introduction for mass spectrometry. Since its original description, numerous research papers and review articles have appeared on various aspects of laser mass spectrometry. While most laser ablation/mass spectrometry has been performed with fixed frequency lasers operating at relatively high intensities/fluences ({ge} 10{sup 8} W/cm{sup 2}, {ge} 1 J/cm{sup 2}), there has been some recent interest in the use of low-power tunable lasers to ablate and resonantly ionize selected components in the ablation plume. This process has been termed resonant laser ablation (RLA). The authors report here on aspects of RLA behavior for a number of metals, alloys and thin films. The versatility of RLA is demonstrated, with results on a variety of samples and in several mass spectrometers. In addition, the application to depth profiling of thin films and multilayers is described; absolute removal rates and detection limits are also displayed. A discussion of possible mechanisms for low-power ablation is discussed.
Date: December 31, 1995
Creator: Anderson, J.E.; Garrett, A.W.; Gill, C.G.; Hemberger, P.H.; Nogar, N.S.; Allen, T.M. et al.
Partner: UNT Libraries Government Documents Department

Laser desorption in an ion trap mass spectrometer

Description: Laser desorption in a ion-trap mass spectrometer shows significant promise for both qualitative and trace analysis. Several aspects of this methodology are discussed in this work. We previously demonstrated the generation of both negative and positive ions by laser desorption directly within a quadrupole ion trap. In the present work, we explore various combinations of d.c., r.f., and time-varying fields in order to optimize laser generated signals. In addition, we report on the application of this method to analyze samples containing compounds such as amines, metal complexes, carbon clusters, and polynuclear aromatic hydrocarbons. In some cases the ability to rapidly switch between positive and negative ion modes provides sufficient specificity to distinguish different compounds of a mixture with a single stage of mass spectrometry. In other experiments, we combined intensity variation studies with tandem mass spectrometry experiments and positive and negative ion detection to further enhance specificity.
Date: January 1, 1993
Creator: Eiden, G.C.; Cisper, M.E.; Alexander, M.L.; Hemberger, P.H. & Nogar, N.S.
Partner: UNT Libraries Government Documents Department

Use of Stable Noble Gases as a Predictor of Reactor Fuel Type and Exposure

Description: Ensuring spent reactor fuel is not produced to provide weapons-grade plutonium is becoming a major concern as many countries resort to nuclear power as a solution to their energy problems. Proposed solutions range from the development of proliferation resistant fuel to continuous monitoring of the fuel. This paper discusses the use of the stable isotopes of the fissiogenic noble gases, xenon and krypton, for determining the burnup characteristics, fuel type, and the reactor type of the fuel from which the sample was obtained. The gases would be collected on-stack as the fuel is reprocessed, and thus confirm that the fuel is as declared.
Date: August 30, 1999
Creator: Fearey, B.L.; Charlton, W.S.; Perry, R.T.; Poths, J.; Wilson, W.B.; Hemberger, P.H. et al.
Partner: UNT Libraries Government Documents Department

Evaluation of the uranium double spike technique for environmental monitoring

Description: Use of a uranium double spike in analysis of environmental samples showed that a {sup 235}U enrichment of 1% ({sup 235}U/{sup 238}U = 0.00732) can be distinguished from natural ({sup 235}U/{sup 238}U = 0.00725). Experiments performed jointly at Los Alamos National Laboratory (LANL) and Oak Ridge National Laboratory (ORNL) used a carefully calibrated double spike of {sup 233}U and {sup 236}U to obtain much better precision than is possible using conventional analytical techniques. A variety of different sampling media (vegetation and swipes) showed that, provided sufficient care is exercised in choice of sample type, relative standard deviations of less than {+-} 0.5% can be routinely obtained. This ability, unavailable without use of the double spike, has enormous potential significance in the detection of undeclared nuclear facilities.
Date: January 1, 1998
Creator: Hemberger, P.H.; Rokop, D.J.; Efurd, D.W.; Roensch, F.R.; Smith, D.H.; Turner, M.L. et al.
Partner: UNT Libraries Government Documents Department

Detection of radioactive materials at Astrakhan

Description: Astrakhan is the major Russian port on the Caspian Sea. Consequently, it is the node for significant river traffic up the Volga, as well as shipments to and from other seaports on the Caspian Sea. The majority of this latter trade across the Caspian Sea is with Iran. The Second Line of Defense and RF SCC identified Astrakhan as one of the top priorities for upgrading with modern radiation detection equipment. The purpose of the cooperative effort between RF SCC and DOE at Astrakhan is to provide the capability through equipment and training to monitor and detect illegal shipments of nuclear materials through Astrakhan. The first facility was equipped with vehicle and rail portal monitoring systems. The second facility was equipped with pedestrian, vehicle and rail portal monitoring systems. A second phase of this project will complete the equipping of Astrakhan by providing additional rail and handheld systems, along with completion of video systems. Associated with both phases is the necessary equipment and procedural training to ensure successful operation of the equipment in order to detect and deter illegal trafficking in nuclear materials. The presentation will described this project and its overall relationship to the Second Line of Defense Program.
Date: July 1, 1999
Creator: Cantut, L; Dougan, A; Hemberger, P; Kravenchenko, Gromov, A; Martin, D; Pohl, B et al.
Partner: UNT Libraries Government Documents Department