Electron-Scattering Studies on<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mi mathvariant="normal">Ca</mml:mi></mml:mrow><mml:mrow><mml:mn>40</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:math>and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mi mathvariant="normal">Ca</mml:mi></mml:mrow><mml:mrow><mml:mn>48</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:math>

The beam from the Yale University Electron Accelerator has been used in systematic studies of the nuclear charge distributions of ${\mathrm{Ca}}^{40}$ and ${\mathrm{Ca}}^{48}$. The beam energy has been varied between 20 and 60 MeV, and the angular distributions include angles between 70\ifmmode^\circ\else\textdegree\fi{} and 150\ifmmode^\circ\else\textdegree\fi{}. Elastic electron scattering has been used to obtain the rms radius of ${\mathrm{Ca}}^{40}$, and a value for the difference between the ${\mathrm{Ca}}^{40}$ and ${\mathrm{Ca}}^{48}$ radii. The results indicate that this difference is not as large as that predicted by the ${A}^{\frac{1}{3}}$ rule, in agreement with the Stanford electron scattering work and the Chicago and CERN experiments on the spectra from muonic atoms. Inelastic scattering experiments also have been performed, yielding results for the reduced transition probability $B(EL\ensuremath{\uparrow})$ and the transition radius ${R}_{\mathrm{tr}}$ for the following states: ${\mathrm{Ca}}^{40}$, 3.73-MeV (3-), 3.90(2+), 6.94(2+, 3-); ${\mathrm{Ca}}^{48}$, 3.83-MeV (2+) and 4.51-MeV (3-).