Heavy residue production in the interaction of 29 MeV/nucleon {sup 208}Pb with {sup 197}Au
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331 (United States)
- Chalmers University of Technology, Goeteborg (Sweden)
- Studsvik Neutron Research Laboratory, S-611 82 Nykoeping (Sweden)
The yields, recoil properties, and angular distributions of the fragments of the target nucleus were measured for the 29 MeV/nucleon {sup 208}Pb+{sup 197}Au reaction using radiochemical techniques. The fragment isobaric yield distribution and mean energies were deduced from these data. The fission cross section is 2.2{plus_minus}0.5 b while the residue formation cross section is 3.9 b. Heavy residues form a part of a large central bump (usually associated with fission) in the fragment mass distribution. Comparing the data from this reaction to other reactions involving massive nuclei at projectile energies from 7 to 45 MeV/nucleon shows the locus of fragment yields [{sigma}(Z,A)] to be roughly independent of the reacting system or projectile energy. The fragment angular distributions evolve from sidewise peaked (for near target, quasielastic residues) to forward peaked as the mass number decreases. The isomer ratios for the residues indicate their formation from the lowest partial wave events while the fission fragments appear to originate in higher {ital l} events. Attempts to use the nucleon transport model (or some modification of it) to calculate the residue cross sections were only partially successful. It is suggested the the lack of dynamic multifragmentation mechanisms in these models is the cause of the shortcomings. {copyright} {ital 1999} {ital The American Physical Society}
- OSTI ID:
- 322006
- Journal Information:
- Physical Review, C, Vol. 59, Issue 3; Other Information: PBD: Mar 1999
- Country of Publication:
- United States
- Language:
- English
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