The results from a series of experiments that characterize the x-ray flux transmitted through a laser-irradiated Au foil are presented. The purpose of the experiments was to develop a working model for an x-ray source that will create hot, dense plasmas with controllable gradients. These plasmas will be used as a test bed for the study of the complex radiative processes that are intrinsic to the evolution of moderate- and high-[ital Z] matter. The experiments quantitatively measured the time- and frequency-dependent energy transferred to the back of the foil. Angular information and the characterization of the flux as a function of foil thickness are also presented. Tables of the time-dependent flux are given.