Contribution of Coulomb Excitation to Inelastic Scattering between Nuclear Resonances

Abstract

Using the comparison method of Bjerregaard and Huus, we have determined the relative gamma-ray yields for thin targets (∼10 kev) of ${\mathrm{F}}^{19}$ (198-kev state) and ${\mathrm{Na}}^{23}$ (446-kev state), with protons and alpha particles over energy intervals corresponding to the same values of $\xi$, the adiabatic parameter in Coulomb excitation. Between the proton resonances we found that the yield ratios agreed closely with those predicted for $E2\mathrm{}$ Coulomb excitation, and differed by about 50% from $E1\mathrm{}$ (or $E3\mathrm{}$) excitation. Thus the nonresonant inelastic scattering yield between proton resonances in these light nuclei can be entirely accounted for by Coulomb excitation of the $E2\mathrm{}$ type. We determined a slight, negative anisotropy in the angular distribution of the 446-kev gamma ray following Coulomb excitation of ${\mathrm{Na}}^{23}$, fixing the spin of that state at $\frac{5}{2^{+}}$.