Muonic X Rays from Separated Isotopes of Europium

Muonic $K$ and $L$ x rays have been observed with a Ge(Li) detector for separated isotopes of europium. A modified Fermi charge distribution was used for the analysis of both nuclei. The ${\mathrm{Eu}}^{153}$ spectrum was fitted by assuming the validity of the rotation model; for the ${\mathrm{Eu}}^{151}$, excitation to only the low-lying 21.7-keV state was invoked. The analysis yields values for several level parameters that agree well with the available data.