Yields of Polonium and Bismuth Nuclides fromBi209and Recoil Studies ofBi209(p,p2n)Bi207Reaction at 450 MeV

Abstract

The radioactivity of ${\mathrm{Bi}}^{207}$ produced in the 450-MeV proton bombardment of ${\mathrm{Bi}}^{209}$ has been measured. The yield ratios ${\mathrm{Bi}}^{205}$/${\mathrm{Bi}}^{207}$, ${\mathrm{Bi}}^{206}$/${\mathrm{Bi}}^{207}$, and ${\mathrm{Po}}^{207}$/${\mathrm{Bi}}^{207}$ were determined to be 0.77±0.16, 0.83±0.19, and 0.224±0.013, respectively. These ratios, and Po/Bi ratios for other isobaric pairs of nuclides, are lower than values given by the Metropolis et al. Monte Carlo intranuclear cascade calculations. Examination of available data on absolute yields of Po and Bi nuclides shows that there is an underestimation of ${\mathrm{Bi}}^{209}$ ($p,pxn$) yields in the calculation, a larger discrepancy occurring at ${\mathrm{Bi}}^{207}$ than for lighter Bi nuclides (larger $x$ values). New Monte Carlo calculations by Bertini and by Chen et al. give better agreement with experiments. Recoil properties of ${\mathrm{Bi}}^{207}$ from 450-MeV proton bombardment of ${\mathrm{Bi}}^{209}$ have been measured and compared with results derived from the Metropolis et al. calculations. Over-all agreement is satisfactory, but the transverse momentum component seems overestimated by the calculations, a result found earlier in work with lighter Bi nuclides.