Evaporation residue, fission cross sections, and linear momentum transfer for 14N induced reactions from 35A to 155A MeV.

Abstract

Differential cross sections for evaporation residues and fission fragments for 35A, 100A, 130A and 155A MeV $^{14}\mathrm{N}$ on targets ranging from $^{154}\mathrm{Sm}$ to $^{197}\mathrm{Au}$ have been measured. The angle-integrated cross sections are larger than what might be expected. The fission fragment-fission fragment folding angle correlations for 35A, 100A MeV $^{14}\mathrm{N}$ and 25A MeV $^{16}\mathrm{O}$ on similar targets were also measured. The average linear momentum transfer has been deduced from both the fission angle correlation and from the fore-aft asymmetry of the fission angular distributions in the laboratory system. The data are all consistent with a picture where pre-equilibrium particle emission removes an increasing fraction of the orbital angular momentum as the bombarding energy increases. This allows a large range of partial waves to contribute to formation of a composite nucleus with a finite fission barrier. \textcopyright{} 1996 The American Physical Society.