Elsevier

Nuclear Physics A

Volume 211, Issue 1, 27 August 1973, Pages 1-6
Nuclear Physics A

Half-life of 178m2Hf and its neutron capture production

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Abstract

The half-life of the high-spin isomeric state in 178Hf at > 2.43 MeV has been measured to be 31 ± 1 y. The cross section for production of this isomer in a thermal-reactor neutron spectrum has been measured to be (2 ± 1) × 10−7b. The computation of this value assumes that the burn-up cross section of the isomer is < 20 b, an assumption which is supported by the experimental data.

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  • R.G. Helmer et al.

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  • R.S. Hager et al.

    Nucl. Data

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There are more references available in the full text version of this article.

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    Although this uncertainty does not influence relative chronometry, an improvement is desirable for the absolute time scale. We are currently in the process of performing a new half-life measurement using sample material prepared by Helmer and Reich some 40 years ago, which led to the discovery of the 30-year isomer in 178Hf [8,9]. 182Hf is a typical r-process nuclide, but it can also be produced by the so-called “fast” s-process in massive stars [10].

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Work performed under the auspices of the US Atomic Energy Commission.

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