Neutron Activation Cross Sections of Pm¹⁴⁷, Pm¹⁴⁸, and Pm^148m

The thermal cross sections and the resonance integrals have been measured for the activation of Pm¹⁴⁷ to both Pm¹⁴⁸ isomers. The thermal activation cross sections are: 124 ± 13 barns to 5.39-day Pm¹⁴⁸ and 111 ± 11 barns to 40.6-day Pm^148m. The resonance integrals are: 1700 ± 250 barns to 5.39-day Pm¹⁴⁸ and 1520 ± 230 barns to 40.6-day Pm^148m. Approximate cross sections have been obtained for neutron capture by both Pm¹⁴⁸ isomers. The pile cross section of 40.6-day Pm^148m is 29,000 ± 5000 barns and is due mainly to thermal neutron capture. The pile cross section of 5.39-day Pm¹⁴⁸ is 3,000 ± 2,000 barns and is due mainly to resonance neutron capture.