Mass-Spectrometric Study of Deuteron-Induced Reactions in Iodine

Abstract

Absolute cross sections for the ($d, 2n$), ($d, 3n$), and ($d, p$) plus ($d, n$) reactions in ${\mathrm{I}}^{127}$ have been measured for deuteron energies up to 18 Mev by the method of isotope dilution. The stable and long-lived isotopes of xenon produced by deuteron bombardment of stacked foils of KI were distilled from these foils, were mixed with known quantities of atmospheric xenon, and after purification were examined for isotopic composition in a mass spectrometer. For purposes of comparison, relative activation cross sections for the ($d, p$) reaction on ${\mathrm{I}}^{127}$ were measured by standard counting techniques. The cross section for the formation of the compound nucleus ${\mathrm{Xe}}^{129}$ is found to be in good agreement with theoretical calculations if the interaction radius is taken to be $(1.3\mathrm{}{A}^{\frac{1}{3}}+1.21){10}^{-13\mathrm{}}$ cm. The curves for the yield of ${\mathrm{I}}^{128}$ and for the total production of ${\mathrm{Xe}}^{128}$ are of the same shape. It is argued that the ($d, p$) and ($d, n$) stripping reactions are the principal mechanism for the formation of this latter nuclide. A precise mass-spectrometric determination of the half-life of ${\mathrm{Xe}}^{127}$ yields a value of 36.406±0.016 days.