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  • Author or Editor: G. Harbottle x
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Abstract  

A procedure first described by O. Hahn in 1935 has been adapted to the measurement of the probability of escape of radon and thoron//the emanation fraction/ in soils and rocks through application of the germanium counter. Measurement of the regrowth of the214Pb, Bi,212Pb, Bi and208Tl following emanation loss permits the simultaneous determination of the two emanation fractions.

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Abstract  

The half-life of207Bi has been redetermined as 32.7±0.8 years. A new set of gamma-ray abundances are aslo calculated.

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Abstract  

A226 Ra source of known disintegration rate has been measured to determine the absolute -ray emission intensities of members of its decay chain in radioactive equilibrium. The results are compared with other values from the literature.

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Abstract  

A232Th source of knowsn disintegration rate and in secular equilibrium was measured to determine the absolute -ray emission intensities of members of its decay chain. Similar measurements were made on sources of highly-enriched235U and of normal uranium metal. The results are compared with values from the literature.

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Abstract  

Two fundamentally different standardization systems, widely used in the neutron activation analysis of archaeological ceramics and of other materials, have been intercompared using procedures of high precision. The results should permit data standardized under either system to be transformed to the opposite system. The two systems are generally known as the Asaro-Perlman standard and the BNL Six-Rocks standard.

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Abstract  

Museum collections include many French medieval limestone sculptures of unknown origin. To localize the source of their stone, the composition of samples from such sculptures has been determined by neutron activation analysis (INAA). Using multivariate statistics, we compared their compositional profiles with groups of samples from French monuments and from quarries known to medieval craftsmen. This process has suggested a provenance for some sculptures and allowed us to assign others to a region or a quarry that provided stone for their production.

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Abstract  

The enormous utilization of phosphate rock and super phosphate derived from it have the potential of being an important factor in the contamination of aquifers with alpha emitting radionuclides and heavy metals. Both rock phosphate and super phosphate contain substantial levels of natural uranium, amounting to hundreds of ppm. Our study has shown that whereas the uranium series in phosphate rock is nearly in secular equilibrium, in super phosphate the226Ra and its progeny are depleted by 60–70%. This is a result of the chemical processing of the rock phosphate. On the other hand the super phosphate is much more soluble and can be expected to release its radionuclides to the environment more rapidly than rock phosphate. The present study explores the release of radioisotopes and heavy metals from phosphate fertilizers. Extensive analytical use has been made of a germanium well-detector/Compton suppression system.

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