Thresholds forSn116(p, n)andSn118(p, n)

The ${}_{}{}^{116}{}_{}{}^{}\mathrm{Sn}(p, n)$ and ${}_{}{}^{118}{}_{}{}^{}\mathrm{Sn}(p, n)$ thick-target integrated cross sections were measured up to about 100 keV above the thresholds and fitted by the Hauser-Feshbach statistical theory. It is shown for these nuclei that the familiar plot of the thick-target yield to the two-thirds power is not valid, except for an impractical region very near threshold. It is also shown that $\gamma$-ray emission dominates over neutron and proton emission for more than 100 keV above each threshold. The deduced thresholds are 5531 ± 6 keV for ${}_{}{}^{116}{}_{}{}^{}\mathrm{Sn}$ and 4477 ± 3 keV for ${}_{}{}^{118}{}_{}{}^{}\mathrm{Sn}$. The corresponding $Q$ values, 5483 ± 6 keV and 4439 ± 3 keV, disagree with values from the literature.