0000000000075349

AUTHOR

G. Pascal

showing 4 related works from this author

Observer for a thick layer of solid deuterium-tritium using backlit optical shadowgraphy and interferometry.

2007

Our work is in the context of the French "laser megajoule" project, about fusion by inertial confinement. The project leads to the problem of characterizing the inner surface, of the approximately spherical target, by optical shadowgraphy techniques. Our work is entirely based on the basic idea that optical shadowgraphy produces "caustics" of systems of optical rays, which contain a great deal of 3D information about the surface to be characterized. We develop a method of 3D reconstruction based upon this idea plus a "small perturbations" technique. Although computations are made in the special "spherical" case, the method is in fact general and may be extended to several other situations.

Physicsbusiness.industryMaterials Science (miscellaneous)Context (language use)Observer (special relativity)ShadowgraphyLaserIndustrial and Manufacturing Engineeringlaw.inventionInterferometryOpticslawBusiness and International ManagementPerturbation theorybusinessInertial confinement fusionLaser MégajouleApplied optics
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Spatial Reconstruction Algorithm of DT Layer in Cryogenic Targets Using Optical Techniques

2007

The measurements of the solid DT layer, in terms of thickness and roughness, in the LMJ geometry (i.e. in a hohlraum) are not trivial. The DT layer measurements will be done using a Matsukov-Cassegrain telescope placed 39 cm away from the target. This telescope will be used to acquire shadowgraphy images on equators, and interferometric measurements on pole areas using optical coherence tomography (OCT). Optical coherence tomography allows determining the DT layer thickness on a few points, in the polar regions of the target. By scanning around the poles, several points can be acquired in order to calculate the roughness and the local shape of the DT layer at the pole. Both techniques were …

Nuclear and High Energy Physics020209 energy02 engineering and technologySurface finishShadowgraphy01 natural sciences010305 fluids & plasmaslaw.inventionTelescopeOpticsOptical coherence tomographyHohlraumlaw0103 physical sciences0202 electrical engineering electronic engineering information engineeringmedicineGeneral Materials ScienceCivil and Structural EngineeringPhysicsmedicine.diagnostic_testbusiness.industryMechanical EngineeringReconstruction algorithmInterferometryNuclear Energy and EngineeringbusinessLayer (electronics)Fusion Science and Technology
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A Model to Characterize the D-T Layer of ICF Targets by Backlit Optical Shadowgraphy

2005

A numerical model is presented in order to modelize the bright ring that appears in backlit optical shadowgraphy on a transparent hollow sphere with a solid deuterium-tritium layer inside. This novel model is based on computational calculations applied to the problem of the targets used in inertial confinement fusion. The model takes into account the influences of the optical imaging system (numerical aperture, source divergence, camera resolution, etc.) and the effect of the capsule itself, diameter, thickness, and refractive index, and allows one to analyze the inner surface of a capsule in terms of thickness and roughness.

Nuclear and High Energy PhysicsMaterials scienceComputer simulationbusiness.industry020209 energyMechanical Engineering02 engineering and technologySurface finishBacklightShadowgraphy01 natural sciences010305 fluids & plasmasNumerical apertureOpticsNuclear Energy and EngineeringPhysics::Plasma Physics0103 physical sciences0202 electrical engineering electronic engineering information engineeringGeneral Materials SciencebusinessImage resolutionRefractive indexInertial confinement fusionCivil and Structural EngineeringFusion Science and Technology
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Antioxidants and health

1998

National audience

[SDV] Life Sciences [q-bio][SDV]Life Sciences [q-bio]CANCERComputingMilieux_MISCELLANEOUS
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