CROSS SECTIONS AND RESONANCE INTEGRALS FOR THE NEUTRON ACTIVATION OF ¹⁰³Rh

Abstract

The cadmium ratio method has been used to determine the ratio I′/σ 0 for activation of 103 Rh, where I′ is the reduced resonance integral and σ 0 is the 2 200-m/s cross section. For the production of 104g Rh we obtain I′/σ 0 = 8.1 ± 0.3 and, for 104m Rh, I′/σ 0 = 7.4 ± 0.3. These results disagree with a value of ~3.5 obtained in an earlier cadmium ratio measurement. We have also measured the half-lives of the two isomers. In the following table, which summarizes our results, the thermal cross sections are normalized to an absorption cross section in 103 Rh of 146 barns and a value of 12.2 for the production of 104g Rh relative to 104m Rh per 103 Rh capture.[Formula: see text]The total reduced resonance integral is 1 175 barns for activation compared with a value of 1 015 ± 25 barns for absorption derived from published resonance parameters.