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15 recordsLinked to original sources
USGS1982

Chemical characterization of gas- and oil-bearing shales by instrumental neutron activation analysis

The concentration of As, Ba, Ca, Co, Cr, Cs, Dy, Eu, Fe, Ga, Hf, K, La, Lu, Mn, Mo, Na, Ni, Rb, Sb, Sc, Se, Sm, Sr, Ta, Tb, Th, U, Yb, and Zn were determined by instrumental neutron activation analysis in block shale samples of the New Albany Group (Devonian-Mississippian) in the in the Illinois Basin. Uranium content of the samples was as high as 75 ppm and interfered in the determination of samarium, molybdenum, barium and cerium. In the determination of selenium a correction was made for interference from tantalum. U, As, Co, Mo, Ni and Sb as well as Cu, V and pyritic sulphur which were determined by other methods, were found to correlate positively with the organic carbon content of the samples. ?? 1982 Akade??miai Kiado??.

Journal of Radioanalytical Chemistry↗
USGS1977

The precision and accuracy of iterative and non-iterative methods of photopeak integration in activation analysis, with particular reference to the analysis of multiplets

The relative precisions obtainable using two digital methods, and three iterative least squares fitting procedures of photopeak integration have been compared empirically using 12 replicate counts of a test sample with 14 photopeaks of varying intensity. The accuracy by which the various iterative fitting methods could analyse synthetic doublets has also been evaluated, and compared with a simple non-iterative approach. ?? 1977 Akade??miai Kiado??.

Journal of Radioanalytical Chemistry↗
USGS1977

Application of epithermal neutron activation in multielement analysis of silicate rocks employing both coaxial Ge(Li) and low energy photon detector systems

The instrumental activation analysis of silicate rocks using epithermal neutrons has been studied using both high resolution coaxial Ge(Li) detectors and low energy photon detectors, and applied to the determination of 23 elements in eight new U.S.G.S. standard rocks. The analytical use X-ray peaks associated with electron capture or internal conversion processes has been evaluated. Of 28 elements which can be considered to be determinable by instrumental means, the epithermal activation approach is capable of giving improved sensitivity and precision in 16 cases, over the normal INAA procedure. In eleven cases the use of the low energy photon detector is thought to show advantages over convertional coaxial Ge(Li) spectroscopy. ?? 1977 Akade??miai Kiado??.

Journal of Radioanalytical Chemistry↗
USGS1972

A neutron activation analysis procedure for the determination of uranium, thorium and potassium in geologic samples

A neutron activation analysis procedure was developed for the determination of uranium, thorium and potassium in basic and ultrabasic rocks. The three elements are determined in the same 0.5-g sample following a 30-min irradiation in a thermal neutron flux of 2·10 12 n·cm −2 ·sec −1 . Following radiochemical separation, the nuclides 239 U (T=23.5 m), 233 Th (T=22.2 m) and 42 K (T=12.36 h) are measured by β-counting. A computer program is used to resolve the decay curves which are complex owing to contamination and the growth of daughter activities. The method was used to determine uranium, throium and potassium in the U. S. Geological Survey standard rocks DTS-1, PCC-1 and BCR-1. For 0.5-g samples the limits of detection for uranium, throium and potassium are 0.7, 1.0 and 10 ppb, respectively.

Journal of Radioanalytical Chemistry↗
USGS1977

Survey of trace elements in coals and coal-related materials by neutron activation analysis

Utilizing primarily instrumental neutron activation analysis (INAA) and other analytical methods as many as 61 elements were quantitatively surveyed in 170 U.S. whole coals, 70 washed coals, and 40 bench samples. Data on areal and vertical distributions in various regions were obtained along with extensive information on the mode of occurrence of various elements in the coal matrix itself. ?? 1977 Akade??miai Kiado??.

Journal of Radioanalytical Chemistry↗
USGS1982

Anion-exchange separation of Pt and Pd using perchloric and hydrochloric acid solutions

On Biorad Ag-1X8 anion-exchange resin (200-400 mesh), Pd and Pt may be separated from one another by elution with 0.2M HClO4, and 5M HClO4, respectively. If present, Au may be retained by making the elutriants 0.003M in HCl. Alternatively, reduction by H2SO3 enables elution of Pt2+ with 6M HCl before recovery of Pd2+ with 0.2M HClO4??Ir4+ is reduced to Ir3+ by H2SO3 and may be eluted ahead of Pt2+ by 2M HCl. ?? 1982 Akade??miai Kiado??.

Journal of Radioanalytical Chemistry↗
USGS1987

Computer graphics for quality control in the INAA of geological samples

A data reduction system for the routine instrumental activation analysis of samples is described, with particular emphasis on interactive graphics capabilities for evaluating analytical quality. Graphics procedures have been developed to interactively control the analysis of selected photopeaks during spectral analysis, and to evaluate detector performance during a given counting cycle. Graphics algorithms are also used to compare the data on reference samples with accepted values, to prepare quality control charts to evaluate long term precision and to search for systematic variations in data on reference samples as a function of time. ?? 1987 Akade??miai Kiado??.

Journal of Radioanalytical and Nuclear Chemistry A↗
USGS1987

Neutron activation determination of iridium, gold, platinum, and silver in geologic samples

Low-level methods for the determination of iridium and other noble metals have become increasingly important in recent years due to interest in locating abundance anomalies associated with the Cretaceous and Tertiary (K-T) boundary. Typical iridium anomalies are in the range of 1 to 100 ??g/kg (ppb). Thus methods with detection limits near 0.1 ??g/kg should be adequate to detect K-T boundary anomalies. Radiochemical neutron activation analysis methods continue to be required although instrumental neutron activation analysis techniques employing elaborate gamma-counters are under development. In the procedure developed in this study samples irradiated in the epithermal neutron facility of the U. S. Geological Survey TRIGA Reactor (Denver, Colorado) are treated with a mini-fire assay technique. The iridium, gold, and silver are collected in a 1-gram metallic lead button. Primary contaminants at this stage are arsenic and antimony. These can be removed by heating the button with a mixture of sodium perioxide and sodium hydroxide. The resulting 0.2-gram lead bead is counted in a Compton suppression spectrometer. Carrier yields are determined by reirradiation of the lead beads. This procedure has been applied to the U.S.G.S. Standard Rock PCC-1 and samples from K-T boundary sites in the Western Interior of North America. ?? 1987 Akade??miai Kiado??.

Journal of Radioanalytical and Nuclear Chemistry A↗
USGS1984

Determination of uranium concentration in water by liquid anion exchange-delayed neutron analysis

Dissolved uranium is selectively removed from 11 of filtered, acidified water using a liquid anion exchange resin (Amberlite LA-1) dissolved in 10 ml of purified kerosene. The organic phase is then analyzed by a standard delayed neutron counting technique. Yields of removed uranium are consistently greater than 90 percent over a measured concentration range of 1.0 to 100 ppb uranium. The absolute detection limit based on 11 of water is 0.06 ppb. Elemental interferences are minimal and the results compare favorably with fluorometric analyses of natural waters.

Journal of Radioanalytical and Nuclear Chemistry↗
USGS1987

Measurements of210Pb,137Cs, organic carbon and trace elements in sediments of the Illinois and Mississippi rivers

Radiometric dating of sediment accumulations by137Cs and210Pb has been successfully initiated in the Illinois and Mississippi Rivers. Sedimentation rates measured at 13 locations range from 0.7 to 3.6 cm/y. Chemical analysis has been completed for up to 45 major and trace elements in core samples. The upper Illinois River contains higher metal levels than the Mississippi River. The amount of carbon (energy) lost to sediments in large floodplain rivers is estimated between 370 and 4000 g/m2/y. ?? 1987 Akade??miai Kiado??.

Journal of Radioanalytical and Nuclear Chemistry A↗
USGS1987

INAA determination of major and trace elements in loess, paleosol and precipitation layers in a pleistocene Loess Section, China

Instrumental neutron activation analysis was used for the determination of 31 major and trace elements in 32 samples from the Xinji Loess Section, Shaanxi Province, China. Interferences, including those from uranium fission products, were evaluated and corrections applied where necessary. The 39.7-meter deep section comprises of Lishi Loess of the middle Pleistocene (Q2) and Malan Loess of the late Pleistocene (Q3). The section is characterized by the presence of 5 layers of paleosol, and each paleosol is underlain by a precipitation layer. When the elemental abundances are converted to a carbonate-free basis, there is little compositional difference among the carbonate-free fractions of loess, paleosol and precipitation layers. This indicates that dissolution of carbonate minerals by downward-moving surface water was an important process in paleosol formation while other minerals were not severely weathered and elemental fractionation was minimal. The parent materials of the paleosol and precipitation layers closely resemble the loess layers in their elemental abundances, which suggests that all layers in the section have a compositionally similar source. ?? 1987 Akade??miai Kiado??.

Journal of Radioanalytical and Nuclear Chemistry A↗
USGS1985

Analysis of low levels of rare earths by radiochemical neutron activation analysis

A procedure for the radiochemical neutron-activation analysis for the rare earth elements (REE) involves the separation of the REE as a group by rapid ion-exchange methods and determination of yields by reactivation or by energy dispersive X-ray fluorescence (EDXRF) spectrometry. The U. S. Geological Survey (USGS) standard rocks, BCR-1 and AGV-1, were analyzed to determine the precision and accuracy of the method. We found that the precision was ??5-10% on the basis of replicate analysis and that, in general the accuracy was within ??5% of accepted values for most REE. Data for USGS standard rocks BIR-1 (Icelandic basalt) and DNC-1 (North Carolina diabase) are also presented. ?? 1985 Akade??miai Kiado??.

Journal of Radioanalytical and Nuclear Chemistry A↗
USGS2005

Indoor radon risk potential of Hawaii

A comprehensive evaluation of radon risk potential in the State of Hawaii indicates that the potential for Hawaii is low. Using a combination of factors including geology, soils, source-rock type, soil-gas radon concentrations, and indoor measurements throughout the state, a general model was developed that permits prediction for various regions in Hawaii. For the nearly 3,100 counties in the coterminous U.S., National Uranium Resource Evaluation (NURE) aerorad data was the primary input factor. However, NURE aerorad data was not collected in Hawaii, therefore, this study used geology and soil type as the primary and secondary components of potential prediction. Although the radon potential of some Hawaiian soils suggests moderate risk, most houses are built above ground level and the radon soil potential is effectively decoupled from the house. Only underground facilities or those with closed or recirculating ventilation systems might have elevated radon potential. ?? 2005 Akade??miai Kiado??.

Journal of Radioanalytical and Nuclear Chemistry↗
USGS2006

Determination of bromine, chlorine and iodine in environmental aqueous samples by epithermal neutron activation analysis and Compton suppression

Halides, particularly Br- and Cl-, have been used as indicators of potential sources of Na+ and Cl- in surface water and groundwater with limited success. Contamination of groundwater and surface water by Na+ and Cl- is a common occurrence in growing urban areas and adversely affects municipal and private water supplies in Illinois and other states, as well as vegetation in environmentally sensitive areas. Neutron activation analysis (NAA) can be effectively used to determine these halogens, but often the elevated concentrations of sodium and chlorine in water samples can give rise to very high detection limits for bromine and iodine due to elevated backgrounds from the activation process. We present a detailed analytical scheme to determine Cl, Br and I in aqueous samples with widely varying Na and Cl concentrations using epithermal NAA in conjunction with Compton suppression. ?? 2006 Akade??miai Kiado??.

Journal of Radioanalytical and Nuclear Chemistry↗
USGS2003

Mobilization of radionuclides from uranium mill tailings and related waste materials in anaerobic environments

Specific extraction studies in our laboratory have shown that iron and manganese oxide- and alkaline earth sulfate minerals are important hosts of radium in uranium mill tailings. Iron- and sulfate-reducing bacteria may enhance the release of radium (and its analog barium) from uranium mill tailings, oil field pipe scale [a major technologically enhanced naturally occurring radioactive material (TENORM) waste], and jarosite (a common mineral in sulfuric acid processed-tailings). These research findings are reviewed and discussed in the context of nuclear waste forms (such as barium sulfate matrices), radioactive waste management practices, and geochemical environments in the Earth's surficial and shallow subsurface regions.

Journal of Radioanalytical and Nuclear Chemistry↗