Oak Ridge National Laboratory

Physics Division

Physics Division Seminars

Physics Division Seminars bring us speakers on a variety of physics related subjects. Usually these are held in the Building 6008 large Conference Room, at 3:00 pm on the chosen day, but times and locations may vary. For more information, contact our seminar chairman,

Alfredo Galindo-Uribarri
Tel (Office): (865) 574-6124  (FAX): (865) 574-1268

Fri., September 16, 2005, at 11:00 a.m. (refreshments at 10:40 a.m.)

Interaction at the barrier with light RNB's: 17F, 11Be

Cosimo Signorini, University of Padova and INFN, Padova, Italy
Building 6008 Conference Room

Measurements of scattering at Coulomb barrier energies have been performed in the systems 17F+208Pb (at ANL, in collaboration also with ORNL researchers) and 11Be+209Bi (at RIKEN). Both nuclei are very loosely bound, and in addition 11Be has a halo structure. The experiments, done with low intensity RNB, could be done also thanks to a large solid angle, highly segmented setup based on Silicon strip detectors called EXODET.

The reaction cross sections extracted from the data show peculiar behavior. For 17F the reaction cross section is much smaller than the 19F (stable nucleus) induced one; for 11Be compared to the 9Be (stable nucleus weakly bound) one, both cross sections are similar. Finally for the pair 6He, 4He + 209Bi, measured by other groups, the situation is totally reversed compared to the Fluorine one. We believe that part of this is due to the nuclear structure of the projectile with minor influence from the binding energy. This gives several implcations into our understanding of the interactions going on at the barrier.

The program will be continued at LNL with the RNB line recently commissioned.

Host: Dan Shapira, 576-2648