Comparison of the charge distributions of the titanium isotopes

Measurements have been made of the elastic electron scattering from the three even isotopes of titanium, Ti46, Ti48, and Ti50, with the objective of determining the differences in their ground state charge distributions. The experiment measures the ratios of the elastic cross sections of the three isotopes, thereby eliminating many of the uncertainties peculiar to an absolute cross section measurement. The experiment was done at the NBS Linac in Gaithersburg, Maryland. Theoretical calculations using a partial wave elastic scattering program, showed that the ratios of cross sections arising from scattering from two slightly different Fermi type 2 parameter charge distributions, depended strongly on the differences in the parameter describing the charge distribution, but only weakly on the actual values of these parameters. These ratio curves, considered as a function of momentum transfer, achieved their extreme values at momenta transfer near 1.0 F-1, which is near the point where the Born approximation form factor goes to zero. Therefore, ratios of cross sections were measured at momenta transfer ranging from .55 to 1.1 F-1; by holding the scattering angle fixed at 127.50 and varying the incident beam energy from 60 to 123 MeV. 43 refs., 45 figs., 9 tabs