Nonelastic Cross Sections ofPb206andPb208for 14-MeV Neutrons

Abstract

Measurements of the nonelastic cross sections of ${\mathrm{Pb}}^{206}$, ${\mathrm{Pb}}^{208}$, Cu, and Bi for 14-MeV neutrons by the sphere transmission technique are reported. The results are as follows: ${\mathrm{Pb}}^{206}$, 2.50±0.05 b; ${\mathrm{Pb}}^{208}$, 2.58±0.09 b; Bi, 2.53±0.05 b; Cu, 1.44±0.03 b. The values for ${\mathrm{Pb}}^{206}$ and ${\mathrm{Pb}}^{208}$ were computed from the measured nonelastic cross sections of ordinary lead, 2.53±0.05 b, and of radiogenic lead, 2.50±0.04 b. The difference in the cross sections of ${\mathrm{Pb}}^{206}$ and ${\mathrm{Pb}}^{208}$ is much less than that predicted from the one-body alpha decay theory.