Measurement of the 210Po production induced by thermal neutron capture on 209Bi

A measurement of the polonium production in a solid Bi target, placed in a high thermal neutron flux of 2.3 × 1013 n/cm2/s, was performed. Two different activation methods, based on α and γ spectroscopy, were used to cross check the results. Values of (16.08 ± 1.8) mb and (18.4 ± 0.9) mb for the 210Po (i.e. 210gsBi) formation cross-section were obtained and a recommended value of (17.9 ± 0.8) mb was proposed. Our results are in disagreement with adopted cross-section values in the main nuclear data libraries, namely smaller by 25% for 210gsBi. These new values will account for more precise evaluations of 210Po formation in moderated spallation targets containing 209Bi.