(p,p′n), (p,p′γ), and (p,np′) Reactions onSn119andNi61

The Weisskopf-Ewing assumption-that an ($x,yn$) reaction occurs with nearly unit probability if the first emitted particle, $y$, comes off with sufficiently low energy to make neutron emission energetically possible-is tested by coincidence studies of ($p,{p}^{\ensuremath{'}}n$) and ($p,{p}^{\ensuremath{'}}\ensuremath{\gamma}$) reactions on ${\mathrm{Sn}}^{119}$ and ${\mathrm{Ni}}^{61}$ and found to be grossly in error. In particular, ($p,{p}^{\ensuremath{'}}\ensuremath{\gamma}$) competes favorably with ($p,{p}^{\ensuremath{'}}n$) even when neutron emission is energetically possible by \ensuremath{\sim}2 MeV. In ${\mathrm{Sn}}^{119}$, the detailed shape of the energy spectrum of neutrons implies that spectra are drastically non-Maxwellian at low energies.