Two-Step Processes in the exp 40 Ca( Alpha , exp 3 He) exp 41 Ca Reaction

摘要

The exp 40 Ca( alpha , exp 3 He) reaction has been studied at 36 MeV incident energy. About fifty levels have been observed up to 7.1 MeV excitation energy and angular distributions were measured from 6 deg to 60 deg, using a split-pole spectrometer. A local zero-range DWBA analysis has been carried out, and the deduced l-assignments and spectroscopic factors are compared with those obtained from previous neutron stripping experiments. Core-excited states in exp 41 Ca with a(3 exp - , f7/2 ), (2 exp + , f7/2 ) and (5 exp - , f7/2 ) component previously observed in inelastic scattering experiments, are selectively excited by the ( alpha , exp 3 He) reaction. Their angular distributions are compared with coupled-reaction-channel calculations, assuming a pure two-step reaction mechanism. The agreement between theory and experiment may be considered as rather satisfactory for a number of levels. In particular the 1/2 exp + and 3/2 exp + levels and the high spin states with Jsup( pi )=9/2 exp - , 11/2 exp + , 15/2 exp + and 17/2 exp + are successfully described within the framework of the weak-coupling model. (Atomindex citation 13:691210)