14-MeV-Neutron Production of Isomeric States for Several Rare-Earth Elements

Abstract

Fast-neutron cross sections have been determined for the following reactions, using 14-MeV neutrons from the ${\mathrm{H}}^3\mathrm{}(d,n)\mathrm{}{\mathrm{He}}^4$ reaction: ${\mathrm{Y}}^{89}(n,n^{\prime }\gamma ){\mathrm{Y}}^{89m}$, 400 mb; ${\mathrm{Nd}}^{142}\mathrm{}(n,2n)\mathrm{}{\mathrm{Nd}}^{141m}$, 545 mb; ${\mathrm{Sm}}^{144}\mathrm{}(n,2n)\mathrm{}{\mathrm{Sm}}^{143m}$, 400 mb; ${\mathrm{Yb}}^{159}\mathrm{}(n,2n)\mathrm{}{\mathrm{Tb}}^{158m}$, 160 mb; ${\mathrm{Er}}^{168}\mathrm{}(n,2n)\mathrm{}{\mathrm{Er}}^{167m}$, 190 mb. Possible sources of error affecting the cross-section measurements have been discussed and evaluated numerically. The over-all accuracy was determined to be about ±12%.