Neutron capture cross sections of Os-186, Os-187, and Os-189 for the Re-Os chronology

作者：Segawa M^*; Masaki T; Nagai Y; Temma Y; Shima T; Mishima K; Igashira M; Goriely S; Koning A; Hilaire S

来源：Physical Review C, 2007, 76(2): 022802.

DOI：10.1103/PhysRevC.76.022802

Discrete as well as continuum gamma-ray energy spectra from the neutron capture by Os-186, Os-187, and Os-189 have been taken for the first time at 5 <= E-n <= 90 keV by an anti-Compton NaI(Tl) spectrometer. The detection of a weak discrete gamma-ray, about 0.5% of total gamma-ray strength, demonstrates the high sensitivity of the present measurement. The energy spectra enabled us to accurately determine the reaction cross sections with a small systematic uncertainty. Based on the new cross sections, we reestimate on the basis of a careful reaction cross section calculation the correction factor F-sigma for the neutron capture on the 9.75-keV first excited state in Os-187 as a function of stellar temperature, as required to derive the age of the galaxy within the Re-Os chronology.

• 出版日期2007-8
• 单位中国地震局