Experimental study of the 91Zr(n, gamma ) reaction up to 26 keV

Abstract

The neutron capture cross sections of the Zr isotopes are relevant to studies in nuclear structure, nuclear astrophysics, and nuclear technology. The valence neutron of 91Zr with respect to the neutron magic nucleus 90Zr has interesting implications for the statistical analysis in the proximity of shell closures. In stellar nucleosynthesis, the Zr isotopes are important for the s-process reaction flow between the Fe seeds and the heavier isotopes. Because of its relatively small (n, γ ) cross sections, Zr represents also an interesting structural material for nuclear reactors. For the same reason, these cross sections are difficult to measure and reliable data are sparse. Therefore, the (n, γ ) cross sections of the Zr isotopes have been remeasured at the CERN n TOF facility. Thanks to its high instantaneous flux, good energy resolution, and low background, this facility is particularly suited for the determination of small, resonance-dominated cross sections. In this work, results for the 91Zr(n, γ )92Zr reaction are reported in the neutron energy range from thermal to 26 keV. In this region, accurate data of 157 resonances could be obtained, 33 of these resonances are not present in the main databases and/or were observed for the first time.