HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Kline, J. R. Articles by Brar, S. S. Search for Related Content PubMed Articles by Kline, J. R. Articles by Brar, S. S. Agricola Articles by Kline, J. R. Articles by Brar, S. S.

Instrumental Analysis of Neutron Irradiated Soils¹

ABSTRACT

Soils from a worldwide collection were analyzed by gamma ray spectrometry, after thermal neutron activation, to identify and measure trace elements in soils which can be studied by this technique, and to determine whether gamma ray spectra of soils can be used to identify specimens of soil and trace them to their geographical origin. Samples of 100-mg size were irradiated for either 5 or 10 min in the Argonne CP-5 reactor at a thermal neutron flux of 2 x 10¹³ n/cm²/sec. Gamma-ray spectrometry of activated samples was delayed until 4 days after irradiation because of high levels of ²⁴Na which obscured the longer-lived nuclides. Therefore, nuclides with half-lives shorter than 15 hours were not measured. Long-lived nuclides, which could be observed after 4 days of delay are ¹⁴⁰La, ⁴⁶Sc, ⁸²Br, ⁵⁹Fe, ⁵¹Cr, ⁶⁰Co, ¹⁵²Eu, ¹⁵⁴Eu, ¹⁵³Sm, ¹⁸¹Hf, and ⁹⁵Zr-⁹⁵Nb. Quantitative determinations were easily made by nondestructive methods for La, Sc, Fe, Co, Eu, and Sm. Amounts of Sc were correlated with amounts of Fe, Co, and Eu in soils of highly diverse origin. Similar correlations were not obtained with La. Elemental relationships sometimes resulted in similar gamma ray spectra for soils of dissimilar origin. These spectra, therefore, raised doubts as to whether they could be used without other supporting evidence to identify soil specimens or trace them to their place of origin when the analysis is done with NaI crystals and 400-channel analyzers.

¹ Presented before Div. S-2, Soil Science Society of America, Stillwater, Okla., Aug. 21–26, 1966. Work supported by US Atomic Energy Commission.

² Associate Ecologist and Associate Electronics Engineer, Div. of Biological & Medical Research, Argonne National Lab., Argonne, Ill.

Received for publication May 15, 1968. Accepted for publication December 2, 1968.