Elastic scattering of 27.2 MeV alpha particle on 40Ca nucleus

Elastic scattering of 27.2 MeV α particles on 40Ca has been investigated. Differential cross sections have been measured in the angular range from 10 deg to 175 deg in the lab. system. The theoretical analysis has proceeded from the proposition that the results of a calculation based on the optical model in the range of small angles (less than 20 deg for 40Ca) are independent of parameters and shape of the potential employed. Elastic scattering of α particles at angles up to 50 deg has been calculated using three sets of the optical potential parameters in the energy range 23.37-28.92 MeV. In the range of small angles a rather similar behaviour of the calculated curves can be observed whereas in the range of medium and large angles these curves behave very differently. The success in the reproduction of the angular distributions for the entire energy range is indicative of the weak energy dependence of the optical potential parameters for 40Ca. It can be stated that the optical model may be used successfully for the interpretation of the elastic scattering of medium-energy α particles on 40Ca