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The results from a series of experiments that characterize the x-ray flux transmitted through a laserirradiated Au foil are presented. The purpose of the experiments was to develop a working model for anx-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 moderateand high-Z matter. The experiments quantitatively measured the timeand frequencydependent 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.PACS number(s): 52.25.Nr, 52.50.Jm plasmas [5]. Further, the qualities of the emission spectra, i.e. , the quasicontinuous spectral nature and the controllable duration, have proved extremely useful in the development of absorption sources in the x-ray region [6]. Second, the plasma produced by the interaction of the laser with a high-Z material is of interest in the study of laser-rnatter coupling. The formation of gradients, coronal heating, and parametric processes are still the subjects of ongoing investigations [7].Of these studies, a few have been devoted to the x-ray radiation that is transmitted through the back of thin high-Z foils. Investigations were instigated to further understand the energy coupling of the laser to the high-Z 46 7853

The focus of recent efforts at LLNL has been to demonstrate that vapor deposition processing is a suitable technique to form polyimide fnms with sufficient strength for current national ignition facility target specifications. Production of polyimide films with controlled stoichiometry was acccomplished by: 1) depositing a novel co-functional monomer and 2) matching the vapor pressure of each monomer in PMDA/ODA co-depositions. The sublimation and deposition rate for the monomers was determined over a range of temperatures. Polyimide films with thicknesses up to 30 p.m were fabricated. Composition, structure and strength were assessed using FTIR, SEM and biaxial burst testing. The best films had a tensile strength of approximately 100 MPa. A qualitative relationship between the stoichiometry and tensile strength of the film was demonstrated. Thin films (-3.5 ym) were typically smooth with an rms of 1.5 nm.

A Texas Nuclear Cockcroft–Walton neutron generator was refurbished for use as a general fusion-product source. This well-calibrated source is now used routinely for characterizing energetic charged-particle detectors, for the development of nuclear fusion diagnostics, for studying radiation damage, and for calibrating x-ray detectors for laboratory and space plasmas. This paper is an overview of the facility. We describe the main accelerator operating systems, the primary fusion reactions studied, and several diagnostics used to characterize the fusion-product source.