抄録
The angular distributions of the emitted alpha particles from the (d, α) reactions on F19, Ne20, P31 and S32 leading to the ground states and several excited states of the residual nuclei have been measured at an incident deuteron energy of 14.7 Mev. The emitted alpha particles were detected with a solid state detector of a silicon p-n junction.
The alpha particle groups, α0 of the ground state transitions for all targets and the alpha particle groups of several excited state transitions for F19 and S32 show pronounced peaks at forward angles and oscillatory behaviors in the angular distributions, which were compared, and were in good agreement, with the theory of the two nucleon pickup process.
The angular distributions of other alpha particle groups for excited state transitions show nearly symmetrical behaviors about 90° and the cross sections of them are smaller by about a factor of 2∼5 than those of α0. These facts suggest that these reactions occur through different process, and are consistent with the level structures of residual nuclei predicted from the shell model.
The mass number dependence of the integrated cross sections for the ground state transitions was obtained. The values of the cross sections are proportional to the inverse cubes of mass number A and the values of the cross sections for even-even nuclei are larger by about a factor of 3 than those for odd-odd and odd nuclei, in the mass region 14\lesssimA\lesssim 32.
