M. Kowalczyk

HOW MANY FUSION BARRIERS

Fusion barrier distributions for the 20Ne + 112,116,118Sn systems have been extracted from quasi-elastic scattering cross sections measured at the Warsaw HIL Cyclotron. Results are compared to coupled-channels calculations performed with the CCFULL code. The overall widths of the distributions are reproduced on taking account of the low-lying collective states of the target and projectile but some puzzling discrepancies in their shapes remain to be explained.

Some Questions and Answers in Barrier Distributions

We report here preliminary results of experiments concerning the influence of “weak” channels on fusion and quasielastic barrier distributions. Some results of measurements of these distributions in the 20Ne+208Pb system and of transfer probabilities for 20Ne+natNi, 90,92Zr, 118Sn and 208Pb backscattering at near‐barrier energies will be presented.

STRUCTURE OF BARRIER DISTRIBUTIONS: PROBING THE ROLE OF NEUTRON-TRANSFER CHANNELS

In view of its large deformation, which should give rise to strong barrier structures, the 20Ne projectile has been used to study the influence of neutron-transfer channels on the distribution of barrier heights. A previous experiment with a combination of projectiles 20,22Ne suggested that the role of α-particle transfer channels is small. By an appropriate choice of targets (90Zr and 92Zr), having very similar intrinsic structures (excited states and deformation parameters) but giving rise to different Q-values for neutron transfers, we highlight the role of these channels.