A study of the detailed variation of nuclear radius in the region 40 ≤ A ≤ 62 by means of elastic scattering of 42 MeV α particles from 40,42,44,48Ca, 46,48,50Ti, 52Cr, 54,56Fe, 58,60,62Ni

Angular distributions of 42 MeV α particles, elastically scattered from 40,42,44,48Ca, 46,48,50Ti, 52Cr, 54,56Fe, 58,60,62Ni have been measured in the forward region with an absolute accuracy of ±0.1 degree; in particular, the locations of the minima, near 35 degrees (center of mass system) have been determined to within ±0.1 degree. The theoretical analysis has been done in three ways using: (a) the Fraunhofer model, (b) a direct parameterization of the scattering amplitude in terms of 3 parameters, and (c) a standard 4-parameter optical model. Strong absorption radii have been deduced from the critical angular moments extracted from the scattering amplitudes. In addition attempts have been made to determine, for the optical model analysis, other sorts of strong absorption radii which are more characteristic of the scattering than the usual midpoint radius of the potential. Furthermore, in the region where its depth is smaller than 6 to 7 MeV (which corresponds to distances of the order of the strong absorption radii) the optical potential well appears to be well determined and free of the ambiguities associated with the usual parameters. Our analyses indicate that the rate of increase of almost all strong absorption radii is smaller within the Ca isotopes and within the Ti isotopes than within the Fe and Ni isotopes, the radius of 48Ca being anomalously small in all but one type of analysis. (author)