Measurement of the Nuclear Gamma Ray in MuonicSm152

The energy of the first rotational nuclear gamma ray of ${\mathrm{Sm}}^{152}$ in the presence of a muon in a $1s$ state has been found to be 1.03±0.15 keV greater than the normal transition energy. This type of measurement provides a method of determining the change in mean square radius between ground and excited states (isomer shift) in deformed nuclei.