Isospin observables from fragment energy spectra

The energy spectra of light charged particles and intermediate mass fragments from Sn-112 + Sn-112 and Sn-124 + Sn-124 collisions at an incident energy of E / A = 50 MeV have been measured with a large array of silicon strip detectors. We used charged-particle multiplicities detected in an array with nearly 4 pi coverage to select data from the central collision events. We study isospin observables analogous to ratios of neutron and proton spectra, including double ratios and yield ratios of triton/He-3 and of asymmetries constructed from fragments with Z = 3-8. Using the energy spectra, we can construct these observables as functions of kinetic energy. Most of the fragment asymmetry observables have a large sensitivity to sequential decays.