Nuclear Resonance Fluorescence inCu65

Abstract

The 1.114-MeV excited state of ${\mathrm{Cu}}^{65}$ has been investigated by means of nuclear resonant fluorescent scattering and self-absorption experiments. The level width was found to be (1.51±0.38)×${10}^{-3\mathrm{}}$ eV, corresponding to a mean life of (4.4±1.1)×${10}^{-13\mathrm{}}$ sec. Angular-distribution measurements of the resonantly scattered gamma rays gave $\delta ={\left(\frac{E2\mathrm{}}{M1\mathrm{}}\right)}^{\frac{1}{2}}=-{{0.52}_{-0.05\mathrm{}}}^{+0.07\mathrm{}}$. From these values, $B\left(E2\mathrm{}\right)\mathrm{}\downarrow =(0.023\mathrm{}\pm 0.007)\times {10}^{-48\mathrm{}}{e}^2$ ${\mathrm{cm}}^4$ and $B\left(M1\mathrm{}\right)\mathrm{}\downarrow =(0.08\mathrm{}\pm 0.02){\left(\frac{e\hslash }{2Mc}\right)}^2$. The lifetime agrees with other recent measurements, but the value for $\delta$ disagrees with results from Coulomb-excitation experiments.