Mass and charge release by the evaporation of particles from compound nuclei around mass 60

Abstract

Reaction product cross sections have been measured for reactions of⁴He projectile with^54,56Fe,⁵⁸Ni and⁵⁹Co targets in the bombarding energy range 14–27 MeV. The cross-section-weighted average charge$\overline {\Delta Z}$ and mass$\overline {\Delta A}$ removed from the compound system were deduced and compared with results reported for heavy-ion induced reactions. Variation of$\overline {\Delta A}$ with E ^*_CN is independent of the initial angular momentum of compound nucleus in theA=60 mass region in contrary to the rare-earth region. This would suggest a strong angular momentum removal from the compound nucleus by evaporation of particles forA≈60 nuclei. The average evaporated charge$\overline {\Delta Z}$ depends on both the CN excitation energy E ^*_CN and the compound nucleusN andZ numbers. The$\overline {\Delta A}$ and$\overline {\Delta Z}$ dependence on excitation energy and the projectile-target combination can be understood in terms of the statistical model calculations.