Analyses of multifragmentation in terms of the Fisher droplet model (FDM) andthe associated construction of a nuclear phase diagram bring forth the problemof the actual existence of the nuclear vapor phase and the meaning of itsassociated pressure. We present here a physical picture of fragment productionfrom excited nuclei that solves this problem and establishes the relationshipbetween the FDM and the standard compound nucleus decay rate for rare particlesemitted in first-chance decay. The compound thermal emission picture isformally equivalent to a FDM-like equilibrium description and avoids theproblem of the vapor while also explaining the observation of Boltzmann-likedistribution of emission times. In this picture a simple Fermi gas thermometricrelation is naturally justified and verified in the fragment yields and timescales. Low energy compound nucleus fragment yields scale according to the FDMand lead to an estimate of the infinite symmetric nuclear matter criticaltemperature between 18 and 27 MeV depending on the choice of the surface energycoefficient of nuclear matter.
展开▼