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  • Author or Editor: S. Landsberger x
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Abstract  

We have used Compton suppression gamma ray counting to effectively measure 137Cs in undisturbed environmental samples weighing only one hundred grams of material. Our results have shown that Compton suppression is ideal in determining low levels (1–3 Bq/kg) of 137Cs in soil samples, while the Compton advantage is negligible for higher concentrations. Quality assurance and quality control experiments show that for samples weighing 100–200 grams, gamma-ray attenuation is significant (up to 10% difference) when analyzing different soil compositions.

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A program of compositional analysis using neutron activation has been performed on samples of Roman fineware from the Palatine East excavations in Rome at the University of Illinois' TRIGA reactor. These experiments are ultimately intended to assist the authors in advancing the understanding of the organization of pottery production and distribution in central Italy during the late Roman imperial period (4th–5th c. AD). The objectives of this paper are 1) to present an archaeological background of two regionally-produced finewares, 2) to discuss the methods of sampling, irradiation and data analyses, and 3) to demonstrate the preliminary results of our investigation, which included the analyses of Plio-Pleistocene clays from the Janiculum Hill in Rome.

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Arctic pollution is a problem of great concern, because its characteristics (transportation, assimilation into the environment, etc.) are complex and not fully understood. Detection of elemental constituents has been undertaken through the use of neutron activation analysis and Compton suppression (to lower the detection limits for radionuclides characteristic of mainly single gamma-ray emission) to discover possible pollutant sources. The goal of this project was to perform a feasibility study to determine the suitability of neutron activation analysis (NAA) to evaluate cadmium concentrations on air filters collected in the Arctic.

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Standard lead loaded Hypalon gloves deteriorate at an accelerated pace in the glovebox environments of Los Alamos National Laboratory. In an effort to minimize glovebox breaches, a project was undertaken to characterize polymer damage due to various environments. For one such study, experimental techniques were used to facilitate the use of a neutron source in damage studies involving glovebox gloves. In order to identify the radiation field experienced by the polymer samples, a characterization of the neutron source in the experimental setup was needed. The plutoniumberyllium source used was chosen to mimic an average neutron flux in a typical LANL glovebox. However, it was surmised that a more exact experimental flux should be found rather then using merely numerical analysis. Subsequent to ascertaining the impending neutron flux, polyurethane gloves show superior properties when compared against standard leaded Hypalon gloves; however, polyurethane is shown to degrade faster following neutron irradiation.

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Abstract  

Fifty air filters with fine and coarse fractions were prepared from NIST 2710 contaminated soil. Eighteen pairs were made and sent to laboratories of the Coordinated Research Program (CRP) on Applied Research on Air Pollution Using Nuclear-Related Analytical Techniques for elemental determination. The results of this intercomparison are discussed in this paper.

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Airborne particulate matter (APM) was collected in coarse fraction and in PM2.5 during spring of 2002 in Beijing suburban sampling site by Gent SFU sampler. More attention has been paid to the special “events” such as dust, storm and haze. Taking advantage of the combination of thermal or epithermal neutron irradiation with Compton suppression spectrometer system, twenty elemental (Al, Si, Ca, K, Dy, Cu, I, In, Ba, W, Sn, Sb, As, Ti, Br, V, Mn, Cl, Na, Zn) concentration were determined. Among them, several key trace elements that cannot be accomplished by the traditional neutron activation analysis (NAA) were determined. The analysis of trace elemental concentration in PM2.5 shows that the anthropogenic elements such as As, In, Sn, Sb have different trends than crustal elements. The back-trajectories of the high concentration anthropogenic pollution elements revealed their source region. Six potential sources were resolved by positive matrix factorization (PMF), two area type and four source type, as soil, limestone quarry, crop burning and mixture of residue motor and coal burning sampling sites. Taking into account of everyday air particle back trajectories, source compositions together with source regions were also identified.

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Abstract  

During the past decade we have determined the concentrations of a variety of trace elements in the Arctic aerosol by using themal and epithemal neutron activation analysis (NAA). More recently we have employed Compton suppression NAA to lower the detection limits for radionuclides that are characteristic of single or mainly single gamma-ray emission. Using these various methods, we have been able to use elements such as indium and silicon. Furthermore we have achieved extremely low detection limits for iodine, arsenic and antimony. The usefulness of these NAA methods are discussed in a large sampling program that incorporates more than one thousand samples.

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Abstract  

Copper (Cu) is an essential element and is incorporated in many biomolecules that are involved in protecting the brain from oxidative damage. Many brain regions strongly affected by neurodegene rative diseases are small. A sensitive nondestructive procedure to determine Cu is desirable to preserve samples for additional studies. Copper is not easily determined by instrumental neutron activation analysis (INAA) due to high activity levels produced by major abundance elements such as sodium (Na) and chlorine (Cl), which produce a high Compton background. An INAA method involving a short epithermal neutron irradiation and counting with a Compton suppression system was developed to determine Cu in brain, via 5.1-min66Cu. These short irradiation results are compared to those based on coincidence spectrometry of annihilation photons from positron emitting 12.7-h64Cu after a long irradiation.

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Abstract  

Instrumental photon and neutron activation techniques have been compared through the determination of sixteen major, minor and trace constituents in two British Columbian coals and a standard coal. Between the two techniques, the results generally agreed to within one standard deviation with replicate precision being maintained, for both techniques, below twenty percent at worst and down to five percent or better for several elements. Almost all of the elements having environmental, industrial or economic significance in fossil fuels can be determined with good sensitivity by either of these two methods, both of which share the advantages of being non-destructive and multi-element in nature and sufficiently accurate as demonstrated in this paper.

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Abstract  

During the past decade there has been a great emphasis on using multielemental methods to determine heavy metals in solid waste products arising from various industrial, combustion, municipal and mining activities. Furthermore, the study of the leaching characteristics of these solid wastes is of prime importance for environmental and regulatory considerations. We present an overview of neutron activation analysis (NAA), X-ray fluorescence (XRF) and inductively coupled plasma-atomic emission spectroscopy (ICP-AES) for the analysis of solid wastes and leachates. In particular we discuss several matrix problems that are usually not considered in routine NAA measurements.

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