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Photo-disintegration cross section measurements on $^{186}$W, $^{187}$Re and $^{188}$Os: Implications for the Re-Os cosmochronology

T. Shizuma·H. Utsunomiya·P. Mohr·T. Hayakawa·S. Goko·A. Makinaga·H. Akimune·T. Yamagata·M. Ohta·H. Ohgaki·Y. -W. Lui·H. Toyokawa·A. Uritani·S. Goriely
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Abstract

Cross sections of the $^{186}$W, $^{187}$Re, $^{188}$Os($γ,n$) reactions were measured using quasi-monochromatic photon beams from laser Compton scattering (LCS) with average energies from 7.3 to 10.9 MeV. The results are compared with the predictions of Hauser-Feshbach statistical calculations using four different sets of input parameters. In addition, the inverse neutron capture cross sections were evaluated by constraining the model parameters, especially the $E1$ strength function, on the basis of the experimental data. The present experiment helps to further constrain the correction factor $F_σ$ for the neutron capture on the 9.75 keV state in $^{187}$Os. Implications of $F_σ$ to the Re-Os cosmochronology are discussed with a focus on the uncertainty in the estimate of the age of the Galaxy.

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T. Shizuma, H. Utsunomiya, P. Mohr, T. Hayakawa, S. Goko, A. Makinaga, H. Akimune, T. Yamagata, M. Ohta, H. Ohgaki, Y. -W. Lui, H. Toyokawa, A. Uritani, S. Goriely. 2005-06-30. Photo-disintegration cross section measurements on $^{186}$W, $^{187}$Re and $^{188}$Os: Implications for the Re-Os cosmochronology. https://doi.org/10.1103/physrevc.72.025808

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