Temperature and Scaling Studies from Projectile Fragmentation of 86,78Kr+64,58Ni at 35 MeV/A.

摘要

Many observables have been developed to study the effects of the two componentnature of nuclei. This dissertation has experimentally probed caloric curves as wellas scaling observables for their dependence on the asymmetric portion of the nuclearequation of state. Projectile fragmentation sources were identified from the reactionsof 86,78Kr+64,58Ni at 35 MeV/A taken on the NIMROD-ISiS array. The angularcoverage, excellent isotopic resolution, and Neutron Ball allow for quasi-completeevent reconstruction in both charge and mass.A new thermometer for nuclear fragmentation studies has been derived and ispresented here. In this thermometer, the temperature is obtained from fluctuations ofthe transverse momentum. The proton transverse momentum fluctuations are usedin this thesis to study the N/Z dependence of the nuclear caloric curve. The caloriccurve constructed from proton momentum fluctuations does not show a significantdependence on the source N/Z ratio. Two other thermometers have also been studiedin this thesis: the double isotope ratio, and moving source slope thermometers. Thesethermometers show no statistically significant dependence on the source N/Z.The source density has been derived from the evolution of fragment Coulombbarriers with increasing E*/A. This density showed no source N/Z dependence. However,a strong evolution in source density over the E*/A=1.5-7.5 MeV region wasobserved.Fragment scaling was investigated through isoscaling and power law scaling. The power law scaling showed a strong dependence on the source N/Z. This source N/Zdependence was further investigated through isoscaling. The fragment yields of thisdata have been shown to exhibit consistent isoscaling for Z=1-17. In addition, isoscalingwas observed in data cut on the E*/A of the source yielding decreasing slopes (a)as a function of E*/A. This decrease, normalized to the asymmetries of the sources(a/delta), has been linked to a decrease in the asymmetry coefficient Csym.This dissertation has shown that the experimentally observed decrease in Csymwith E*/A is well correlated to the temperature and density changes experimentallyobserved in this data.