Integrated Cross Sections forBi209(γ,xnyp)Reactions

Abstract

Integrated cross sections for the photoproduction of ${}_{}{}^{200-206}{}_{}{}^{}\mathrm{Bi}$ and ${}_{}{}^{200-204}{}_{}{}^{}\mathrm{Pb}$ from ${}_{}{}^{209}{}_{}{}^{}\mathrm{Bi}$ have been measured. A single sample was activated during a 10-minute 137-MeV bremsstrahlung bombardment by the NBS Linac, and $\gamma$ rays from the daughter products was measured with a Ge(Li) spectrometer over a two-month period to obtain relative yields. The yield data were used along with the established ($\gamma ,2n$) integrated cross section and a calculated thick-target bremsstrahlung spectrum to derive integrated cross sections as follows: ${}_{}{}^{206}{}_{}{}^{}\mathrm{Bi}$ (168±25), ${}_{}{}^{205}{}_{}{}^{}\mathrm{Bi}$ (88±22), ${}_{}{}^{204}{}_{}{}^{}\mathrm{Bi}$ (55±16), ${}_{}{}^{203}{}_{}{}^{}\mathrm{Bi}$ (66±23), ${}_{}{}^{202}{}_{}{}^{}\mathrm{Bi}$ (31±12), ${}_{}{}^{201}{}_{}{}^{}\mathrm{Bi}$ (10.7±5.9), ${}_{}{}^{200}{}_{}{}^{}\mathrm{Bi}$ (5.7±3.4), ${}_{}{}^{204}{}_{}{}^{}\mathrm{Pb}$ (8.0±2.4), ${}_{}{}^{203}{}_{}{}^{}\mathrm{Pb}$ (3.8±1.3), ${}_{}{}^{202}{}_{}{}^{}\mathrm{Pb}$ (3.4±1.3), ${}_{}{}^{201}{}_{}{}^{}\mathrm{Pb}$ (15.3±8.4), and ${}_{}{}^{200}{}_{}{}^{}\mathrm{Pb}$ (1.62±.97) MeV mb. Evidence is also presented for an 11.5-h isomeric state in ${}_{}{}^{200}{}_{}{}^{}\mathrm{Pb}$.