4-NUCLEON AND ALPHA-PARTICLE TRANSFER BETWEEN HEAVY-NUCLEI

Using a magnetic spectrometer, data on transfer reactions are obtained in the Pb-208 + Sm-144 system at energies below the Coulomb barrier. They are analysed with respect to the properties of the transfer of two protons and two neutrons. These reactions correspond to alpha-particle removal or addition as well as to two different double-charge exchange reactions. Using the semiclassically defined probabilities for the transfer of two protons and two neutrons, as obtained from the measured data, the four-nucleon transfer can be quantitatively described in three cases by the sequential independent transfer of protons and neutrons in the same or different directions. We compare these results with data obtained using radiochemical methods, where probabilities for alpha-particle transfer can be extracted and the same magnitude as in the Pb-208 + Sm-144 system is observed.