Cross-sections and linear momentum transfer in alpha-induced reactions on Rb-85

Cross-sections for the reactions Rb-85(alpha ,2n)Y-87, Rb-85(alpha ,3n)Y-86 and Rb-85(alpha,alphan)Rb-84 have been determined in the a-energy range of 20-50 MeV. Integral recoil ranges of the evaporation residue for the react ion Rb-85(alpha,alphan)Rb-84 have also been measured. From the recoil range data, the linear momentum transfer to the product nucleus for the above re action has been deduced. The experimental results are compared with theoret ical model predictions. For (alpha ,xn) reactions, the agreement between th e theory and the experiment is found to be quite satisfactory. In case of ( alpha,alphan) reaction, the theoretical calculations fail to reproduce the experimental cross-sections as well as linear momentum transfer even when t he incident alpha -energy is quite low.