Radiative decay of neutron resonances inGe73(n,γ)Ge74

Abstract

$\ensuremath{\gamma}$ rays following neutron capture in natural germanium have been studied up to ${E}_{n}\ensuremath{\approx}500$ eV with the fast chopper at the Brookhaven high flux beam reactor. Up to this energy only resonances in $^{73}\mathrm{Ge}$ contribute. From the high-energy $\ensuremath{\gamma}$ rays observed, levels in $^{74}\mathrm{Ge}$ are identified to an excitation energy of about 3 MeV. From the low-energy $\ensuremath{\gamma}$ rays depopulating the $^{74}\mathrm{Ge}$ levels, spin assignments for several $^{73}\mathrm{Ge}$ resonances are made; namely 102 eV, ${J}^{\ensuremath{\pi}}={4}^{+}$; 204 eV, ${J}^{\ensuremath{\pi}}={5}^{+}$; and 224 eV, ${J}^{\ensuremath{\pi}}={4}^{+}$. The results of the resonance capture experiments are compared to previous "average-resonance" and thermal-capture work, and in general are found to be in good agreement. Average radiative strengths for $M1$ and $E2$ transitions are calculated and compared to model estimates.[NUCLEAR REACTIONS $^{73}\mathrm{Ge}(n,\ensuremath{\gamma})^{74}\mathrm{Ge}$, in resonances to 400 eV; energy levels in $^{74}\mathrm{Ge}$, ${J}^{\ensuremath{\pi}}$, resonance spins, ${\ensuremath{\Gamma}}_{\ensuremath{\gamma}\ensuremath{\lambda}f}$; photon strength functions.]