Measurement of evaporation-residue cross sections with light beams and deformed lanthanide target nuclei

To obtain a better understanding of the fusion reaction, we have focused on reactions involving deformed nuclei. Evaporation residue cross sections of the 169Tm+20Ne reaction were measured, from which we extracted the fusion excitation function. This is compared with literature data of the 169Tm+16O and 165Ho+20Ne systems. Irradiation with 20Ne ion beam has been carried out at the incident energy near the Coulomb barrier, where the effect of nuclear deformation is prominent. The results are consistent with the idea that the degree of deformation has an effect on the threshold value of the excitation functions near the Coulomb barrier.