Measurements of muonic $K\alpha$ isotope shifts for 29 nuclides are described in detail. In most cases, these measurements provide unique information on changes in the nuclear charge distribution. The model dependence of the changes in rms radii derived from the muonic shifts (necessary for comparison with electronic data) is discussed in detail. The muonic shifts in Sr, Zr, and Sn are compared with the relevant electronic measurements; the Ca isotope shifts are compared with the results of recent electron scattering results. Strong shell effects are confirmed at $N=28\mathrm{} \mathrm{and} 88$, viz., ${\mathrm{Ca}}^{48}$ and ${\mathrm{Sr}}^{88}$ are found to have smaller rms charge radii than ${\mathrm{Ca}}^{40}$ and ${\mathrm{Sr}}^{86}$. Precise values are also obtained for the K-Ca isotone shifts and for the absolute energies of nine $K\alpha$ transitions.

• Received 8 April 1968

DOI:https://doi.org/10.1103/PhysRev.173.1088