Publications (7)9.23 Total impact
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Article: Four-objective analysis including an optically thick line to extract electron temperature and density profiles in ICF implosion cores
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ABSTRACT: We discuss a search and reconstruction method for the simultaneous and self-consistent analysis of a set of image intensity spatial profiles from several narrow-band x-ray pinhole images from argon-doped inertial confinement fusion implosion cores, and the space-integrated line spectrum. The atomic and radiation physics model is embedded into an inversion algorithm, which consists of a Pareto genetic algorithm followed by a Levenberg-Marquardt non-linear least-squares-minimization step, in order to extract the core spatial structure. To find out the best combination of experimental objectives for the analysis, two different combinations of objectives, including optically thick argon Lyα line, were tested and their results were compared with the results from a previous 3-objective analysis. © 2007 American Institute of Physics.Journal of Physics Conference Series 06/2008; 112(2):022014. -
Article: Multiobjective method for fitting pinhole image intensity profiles of implosion cores driven by a Pareto genetic algorithm
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ABSTRACT: We discuss a method for the simultaneous and self-consistent fitting of a set of intensity or emissivity spatial profiles from several narrow-band x-ray pinhole images from argon-doped inertial confinement fusion implosion cores, and the space-integrated line spectrum. A Pareto genetic algorithm (PGA) combines the search and optimization capabilities of a single-objective genetic algorithm with the Pareto domination technique of multiobjective optimization. Further, the PGA search is followed up by a fine-tuning step based on a nonlinear least-squares-minimization procedure. The result is a robust search and reconstruction method that finds the optimal core spatial structure subject to multiple constraints. This method is independent of geometry inversions and could take advantage of not only optically thin but also optically thick image data. Results are shown for two combinations of three-objectives based on gated argon He β and Ly β image data and the line spectrum.The Review of scientific instruments 11/2006; · 1.52 Impact Factor -
Chapter: Narrow-band X-ray imaging for core temperature and density maps retrieval of direct drive implosions - art. no. 631716
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ABSTRACT: We present recent results using multi-monochromatic X-ray imaging of direct drive implosions at the OMEGA laser facility. An array of pinholes coupled to a flat multilayer mirror provides multi-spectral images distributed over a wide spectral range. Using Argon as a dopant in the DD-filled plastic shells produces emission images in the Ar He-beta and Ly-beta spectral regions. When used in conjunction with gated imaging detectors the instrument provides images with spatial resolution of similar to 10 mu m and temporal resolution of similar to 50ps. A special algorithm has been developed to reconstruct narrow-band images, which will allow the retrieval of temperature, and density maps of the core as it evolves through peak compression.01/2006: pages 31716-31716; -
Article: Processing of multi-monochromatic x-ray images from indirect drive implosions at OMEGA
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ABSTRACT: We report here on the processing of multi-monochromatic x-ray images recorded with the MMI instrument in a series of stable and low-convergence indirect-drive implosion experiments in which Ar-doped D2-filled plastic shells were imploded with the OMEGA laser system. MMI records numerous narrow-band x-ray images over a broad photon energy range. From these images, specific line- and continuum-based subimages can be extracted. A procedure for processing data from the array of images recorded by MMI was developed and implemented into a convenient interactive data language code. Data from narrow-band x-ray images are critical for diagnosing the spatial structure of ICF implosion cores. © 2003 American Institute of Physics.The Review of scientific instruments 02/2003; 74(3):1951-1953. · 1.52 Impact Factor -
Article: Analysis of the spatial structure of inertial confinement fusion implosion cores at OMEGA
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ABSTRACT: We report on an experimental and modeling study of the spatial structure in indirectly driven implosion cores. To this end, Ar-doped D-2-filled plastic shells were irradiated with the OMEGA laser system. We focus on processing and analysis of data recorded with a new X-ray imager (MMI-2) that records numerous narrow-band images that include both line and continuum emission. The temperature and density gradients are determined by using a multi-objective analysis of X-ray narrow-band images and X-ray line spectra. This analysis self-consistently determines the temperature and density gradients that yield the best fits to the spatially-resolved emissivity and space-integrated spectral line shapes. (C) 2003 Elsevier Science Ltd. All rights reserved.Journal of Quantitative Spectroscopy and Radiative Transfer 01/2003; 81(1-4):487-497. · 3.19 Impact Factor -
Article: Spectroscopic analysis of hot dense plasmas: A focus on ion dynamics
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ABSTRACT: A brief discussion of the standard theory of line broadening is presented together with an analysis of selected laser-driven implosion experiments. The effect of improved theoretical procedures on experimental analysis is discussed. In particular, we consider the combined effects of ion dynamics and opacity on line profiles used in the analysis of these plasmas. The experiments discussed were performed at the University of Rochester Laboratory for Laser Energetics (LLE). The results presented in this paper illustrate the usefulness of plasma line broadening in diagnosing hot dense plasmas and in understanding fundamental plasma processes.Laser and Particle Beams 11/1996; 14(04):713 - 730. · 1.62 Impact Factor -
Article: Spectroscopic analysis of Ar‐doped laser‐driven implosions
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ABSTRACT: In a series of experiments performed at the Laboratory for Laser Energetics plastic microballoons filled with DD and doped with small amounts of Ar were imploded using the Omega laser system. Time‐resolved K‐shell Ar spectra were simultaneously recorded using two spectrographs (SPEAXS and flat‐crystal). We focus on the analysis of the He‐β line and its associated Li‐like satellites. The density and temperature sensitivity of this composite spectral feature has been studied previously [R. C. Mancini et al., Rev. Sci. Instrum. 63, 5119 (1992)]. Here, we use it as a diagnostic. Modeling results take into account the built‐in density and temperature dependence characteristic of the level populations and broadening properties of these transitions; in addition, we also consider the effects of ion dynamics and opacity. To check the consistency of our analysis we include in the model the He‐γ and Ly‐β lines. © 1995 American Institute of Physics.Review of Scientific Instruments 02/1995; · 1.37 Impact Factor
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Institutions
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1996–2008
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University of Rochester
- Laboratory for Laser Energetics (LLE)
Rochester, NY, USA
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