Photoneutron cross sections for118--124Sn and theγ-ray strength function method

Abstract

Photoneutron cross sections were measured for ${}^{118}$Sn, ${}^{119}$Sn, ${}^{120}$Sn, ${}^{122}$Sn, and ${}^{124}$Sn near neutron threshold with quasi-monochromatic laser-Compton scattering $\ensuremath{\gamma}$ rays. A systematic analysis of the present photoneutron data and existing neutron-capture data is made using the $\ensuremath{\gamma}$-ray strength function on the basis of the HFB + QRPA model of $E1$ strength supplemented with a pygmy dipole resonance, which was deduced from a previous study on ${}^{116}$Sn and ${}^{117}$Sn. Radiative neutron capture cross sections for two radioactive nuclei, ${}^{121}$Sn and ${}^{123}$Sn, are deduced through the $\ensuremath{\gamma}$-ray strength function method.