Prescission and postscission charged particle emissions from theF19+159Tb reaction

Prescission and postscission multiplicities of protons and α particles are measured in the ${}_{}{}^{19}{}_{}{}^{}\mathrm{F}$ ${+}^{159}$Tb reaction. The observed prescission multiplicities are enhanced compared to statistical model predictions and the presaddle delay time of around 0.5×${10}^{\mathrm{-}20}$ sec is needed to reproduce both prescission proton and α particle multiplicities. This value is too small to account for the prescission neutron data measured by Newton et al., suggesting a long saddle-to-scission time. The measured postscission multiplicities of protons and α particles indicate that fission fragments are rather colder than the statistical model predictions, but slightly hotter than the estimation from the obseved prescission and postscission neutron multiplicities.