Mechanism of dissipation in heavy-ion reactions

Conference · Thu Jan 01 00:00:00 EST 1987

OSTI ID:6491670

Nix, J R; Sierk, A J

We discuss a new surface-plus-window mechanism for the conversion of nuclear collective energy into internal degrees of freedom at intermediate excitation energies. This novel dissipation mechanism, which results from the long mean free path of nucleons inside a nucleus, involves interactions of either one or two nucleons with the moving nuclear surface and also, for dumbbell-like shapes encountered in heavy-ion reactions and fission, the transfer of nucleons through the window separating the two portions of the system. To illustrate the effect of surface-plus-window dissipation on heavy-ion-fusion reactions we present dynamical calculations for values of the dissipation strength corresponding to 27% and 100% of the Swiatecki wall-formula value, as well as for no dissipation. In addition to dynamical thresholds for compound-nucleus formation in heavy-ion reactions, our new picture describes such other phenomena as experimental mean fission-fragment kinetic energies for the fission of nuclei throughout the periodic system, enhancement in neutron emission prior to fission, short scission-to-scission times in sequential ternary fission, widths of mass and charge distributions in deep-inelastic heavy-ion reactions, and widths of isoscalar giant quadrupole and giant octupole resonances. 32 refs., 2 figs.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 6491670
• Report Number(s): LA-UR-87-1705; CONF-8706113-1; ON: DE87010124
• Resource Relation: Conference: 6. Adriatic international conference on nuclear physics: frontiers of heavy-ion physics, Dubrovnik, Yugoslavia, 15 Jun 1987; Other Information: Portions of this document are illegible in microfiche products
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
FISSION
REACTION KINETICS
HEAVY ION REACTIONS
COMPOUND NUCLEI
FISSION FRAGMENTS
GIANT RESONANCE
KINETIC ENERGY
NEUTRON EMISSION
NUCLEAR POTENTIAL
SHAPE
TERNARY FISSION
CHARGED-PARTICLE REACTIONS
EMISSION
ENERGY
KINETICS
NUCLEAR FRAGMENTS
NUCLEAR REACTIONS
POTENTIALS
RESONANCE
653003* - Nuclear Theory- Nuclear Reactions & Scattering