Cross sections for thermal neutron capture by 180W and 184W

Based on activation measurements with W targets of natural isotopic abundance, the cross sections for thermal neutron capture by 180W and 184W have been determined by comparing the activities of 181W and 185W after activation with that of 187W. Relative to the known cross sections for capture by 186W, after correction of the latter for changes in the recommended γ-ray branching intensities, the values of the thermal cross sections have been determined to be 22.7(16) b for capture by 180W and 1.60(11) b for 184W. The half-life of 187W was re-determined to be 23.80(3) h.