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on the determination of iridium in diverse geological samples employing hpge-coincidence/nai(tl)-anticoincidence spectrometryThis paper reports the Ir content of a variety of geological samples determined by the high-purity Ge-coincidence/NaI(Tl)-anticoincidence gamma-ray spectrometry (henceforth referred to as coincidence/anticoincidence technique) and by the conventional INAA. The advantages of this technique are: (1) the Ir content of the samples is obtained (ppm to a fraction of ppb ranges) not only by the 468.1 keV peak as in the conventional INAA but also by the 784.6 keV and 920.9 keV sum peaks, which gives more confidence in the values obtained; and (2) it is well suited for the samples with high Compton background for which it is difficult to measure the Ir content by the conventional INAA technique. The practical sensitivity of this technique depends on the sample matrix. Under present experimental conditions, it varied from 0.1 ng for Mn nodules and 0.004 ng for Libyan Desert Glass. Iridium values obtained on small (about 1 microg) olivine grains demonstrate the potential application of this new technique to microsamples. The principle and methodology of this new technique as well as its advantages and disadvantages over the conventional INAA are discussed.
Document ID
19900043796
Document Type
Reprint (Version printed in journal)
Authors
Murali, A. V.
(Lunar and Planetary Institute Houston, TX, United States)
Parekh, P. P.
(New York State, Dept. of Health; New York, State University Albany, United States)
Cumming, J. B.
(Brookhaven National Laboratory Upton, NY, United States)
Date Acquired
August 14, 2013
Publication Date
March 1, 1990
Publication Information
Publication: Geochimica et Cosmochimica Acta
Volume: 54
ISSN: 0016-7037
Subject Category
GEOPHYSICS
Funding Number(s)
CONTRACT_GRANT: NASW-4066
CONTRACT_GRANT: DE-AC02-76CH-00016
Distribution Limits
Public
Copyright
Other