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arXiv · 1602.05911

A reanalysis of radioisotope measurements of the $^9$Be$(γ,n)^8$Be cross-section

Alan E. Robinson
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Abstract

The $^9$Be$(γ,n)^8$Be reaction is enhanced by a near threshold $1/2^+$ state. Contradictions between existing measurements of this reaction cross-section affect calculations of astrophysical r-process yields, dark matter detector calibrations, and the theory of the nuclear structure of $^9$Be. Select well-documented radioisotope $^9$Be$(γ,n)$ source yield measurements have been reanalyzed, providing a set of high-accuracy independently measured cross sections. A Breit-Wigner fit of these corrected measurements yields $E_R=1738.8\pm1.9$ keV, $Γ_γ=0.771\pm0.021$ eV, and $Γ_n=268\pm15$ keV for the $1/2^+$ state. A virtual $1/2^+$ state is excluded with 99.3\% confidence.

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Alan E. Robinson. 2016-08-02. A reanalysis of radioisotope measurements of the $^9$Be$(γ,n)^8$Be cross-section. https://doi.org/10.1103/physrevc.94.024613

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