As part of the French Inertial Confinement Fusion program, Commissariat a l'Energie Atomique has developed cryogenic target assemblies (CTAs) for the Laser Migajoule (LMJ) and a program in two stages for the permeation filling of these CTAs: (a) the permeation filling studies with the Study Filling Station cryostats and (b) the design and manufacturing of the whole operational chain of CTA filling facilities. This paper deals with the description of both the cryogenic studying and the filling facilities for the LMJ targets.

The measurements of the solid DT layer, in terms of thickness and roughness, in the LAV 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 demonstrated on a 175 pm thick microshell with a 100,um thick D-2 layer. A reconstruction algorithm was designed to give the whole shape of the DT layer from the partial data given by shadowgraphy and OCT A 3D spatial estimation of the DT layer can be obtained The algorithm efficiency was improved, with the use of 360 points on shadowgraphic image and 11 points on each pole. An estimation of the spatial DT layer shape was given on the first 90 longitudinal modes and on the first 5 equatorial modes.

Smooth solid DT layer inside a plastic spherical shell are needed in order to achieve the ignition on the Laser MegaJoule (LMJ) facility. This paper follows our previous one I and presents the up to date results concerning the quenching and breathing techniques. New analysis software has been made which allowed us to update the results already obtained for the breathing technique. New experiments done on quenching have leaded to obtain a smooth layer for the higher mode down to 2.3 K below the triple point. The time where the roughness NIF specifications are obtained while the temperature is 1,5 K below the triple point is around 6 seconds using the quenching technique. Roughness analyses are made on one axis view. We also discuss other experimental aspects, such as shadowgraphy and redistribution process.

The characterization of the solid DT layer, in terms of thickness and roughness, in the LMJ geometry (hohlraum) is not trivial. The DT layer measurements will be done using a Maksutov-Cassegrain telescope, 39 cm away from the target. This telescope will be used to acquire shadowgraphy images and spectralinterferometry measurements. Shadowgraphy imaging probes the DT layer geometry at the equator of the target. Spectral-interferometry gives the DT layer thickness on one spot on the shell, in the polar regions of the target. By scanning around the poles, severalpoints can be acquired to probe the roughness and the local shape of the DT layer at the poles. This paper presents the spectrainterferometry technique and explains how the DT layer thickness could be deduced from channelled spectra. First experimental results on a 125 mu m thick empty shell are also reported.

The "CEA cryogenic target fabrication project" includes materials and technological researches on the Cryogenic Target Assembly (CTA), the DT filling and cryogenic transport to the LMJ site, and the conformation of the DT solid layer. The Research program to deliver CTAs to LMJ in 2010 is described Some important experimental results have already been obtained and are presented.

Smooth solid DT layers inside a spherical shell are needed in order to achieve ignition on the Laser MegaJoule (LMJ) facility. This paper presents a few novel techniques developed in our lab to achieve the required temperature and surface roughness conditions. Results are presented that confirm our hypotheses and lead us to be confident that we may achieve the requirements for the cryogenic LMJ ignition target.

A numerical model is presented in order to modelize the bright ring that appears in backlit optical shadow-graphy 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.