OpticalModel Analysis of AlphaParticle Scattering by ^{40}Ca from 12 to 18 MeV
Abstract
Sixtyfour point angular distributions for the elastic scattering of α particles by ^{40}Ca have been measured from 12 to 18 MeV in 100keV intervals. The angular range is from 26.7° to 176.1° (c.m.). Opticalmodel fits to these data have been obtained, using a WoodsSaxon real potential and a surface imaginary potential with a form given by the derivative of a WoodsSaxon function. The real wellradius value of 5.2 F has been taken from previous analyses of electron scattering data. A consistent set of the other geometric parameters was chosen by fitting a representative set of five angular distributions covering the entire energy range. With the geometric parameters thus fixed, twoparameter fits to all of the data have been obtained in which the real and the imaginary potential strengths are varied. A fitting criterion which compensates for the large Rutherford contribution to the scattering at forward angles is introduced to improve the fits. Of the ten phaseequivalent potentials with real potential strengths less than 210 MeV, the three with average values of 25, 105, and 132 MeV are traced as functions of energy. A clustermodel calculation which places a bound αparticle state at 5.23 MeV in ^{44}Ti yields a potentialwell depth of 136 MeV, in rather good agreement with the 132MeV average value found in the scattering analysis.
 Publication:

Physical Review
 Pub Date:
 July 1968
 DOI:
 10.1103/PhysRev.171.1241
 Bibcode:
 1968PhRv..171.1241R