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Author Chakraburtty, A. K. ♦ Stevens, C. M. ♦ Rushing, H. C. ♦ Anders, E.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword PHYSICS ♦ ACTIVATION ANALYSIS ♦ AGE ESTIMATION ♦ ASTROPHYSICS ♦ DETECTION ♦ IONIZATION ♦ IRON ♦ ISOTOPE DILUTION ♦ ISOTOPES ♦ MASS SPECTROMETERS ♦ MEASURED VALUES ♦ METEORITES ♦ NEUTRONS ♦ PALLADIUM 107 ♦ QUALITATIVE ANALYSIS ♦ QUANTITY RATIO ♦ SAMPLING ♦ SEPARATION PROCESSES ♦ SILVER 107 ♦ SILVER 109 ♦ SILVER ISOTOPES ♦ SOLUTIONS
Abstract With a view to developing a new dating method based on extinct 6.8 m.y. Pd/sup 107/, silver was isolated from 18 samples of the iron meteorites Bristol, Canyon Diablo, Grant, Odessa, Pinon, Sandia Mountains, and Toluca. The silver concentation (11 to 197 ppb) was determined on an aliquot by isotope dilution and also by neutron activation analysis of separate samples. The isotopic composition was measured by surface ionization on a mass spectrometer. No enrichment of Ag/sup 107/ was detected in any of the samples: the delta Ag/sup 107/ values for Canyon Diablo and toluca were 1.2 plus or minus 2.3 and 3.5 plus or minus 3.7 per mil, compared with Murthy's values of 40 plus or minus 4 and 22 plus or minus 4 per mil. The grand average of all analyses was 0 plus or minus 1.5 per mil. That this discrepancy was not due to contamination is shown by the low blanks (<5 per cent), by the agreement of the neutron activation and isotope dilution results, and by other evidence. Sampling error is also not a likely explanation, since its probability is < 1.6 x 10/sup -3/ under the most favorable assumptions. Possibly the apparent anomalies found by Murthy are in some way related to the anomalous value he obtained for terrestrial silver (Ag/ sup 107//Ag/sup 109/ = 1.064 plus or minus 0.002, compared with 1.082 plus or minus 0.002, the average ratio found by four other investigators). (auth)
ISSN 00221406
Educational Use Research
Learning Resource Type Article
Publisher Date 1964-02-01
Publisher Department Univ. of Chicago
Journal Journal of Geophysical Research
Volume Number 69
Technical Publication No. EFINS-63-57
Organization Univ. of Chicago


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