The Laser Mégajoule (LMJ) facility has about 40 large optics per beam. For 22 bundles with 8 beams per bundle, it will contain about 7.000 optical components. First experiments are scheduled at the end of 2014. LMJ components are now being delivered. Therefore, a set of acceptance criteria is needed when the optical components are exceeding the specifications. This set of rules is critical even for a small non-conformance ratio. This paper emphasizes the methodology applied to check or re-evaluate the wavefront requirements of LMJ large optics. First we remind how LMJ large component optical specifications are expressed and we describe their corresponding impacts on the laser chain. Depending on the location of the component in the laser chain, we explain the criteria on the laser performance considered in our impact analyses. Then, we give a review of the studied propagation issues. The performance analyses are mainly based on numerical simulations with Miró propagation simulation software. Analytical representations for the wavefront allow to study the propagation downstream local surface or bulk defects and also the propagation of a residual periodic aberration along the laser chain. Generation of random phase maps is also used a lot to study the propagation of component wavefront/surface errors, either with uniform distribution and controlled rms value on specific spatial bands, or following a specific wavefront/surface Power Spectral Distribution (PSD).
One way to achieve fusion in laboratory consists in heating and compressing, by using a laser, a capsule
containing a deuterium - tritium mix. Achievement of such a project can be obtained only through the development of a
new generation of laser facilities. With this end in view, CEA is developing the "Laser Mega-Joule" (LMJ), a facility
made of 240 laser lines. The "Ligne d'Intégration Laser" (LIL) is a prototype of the LMJ made of a four laser lines
assembly. Presently operational, it must permit the validation of the technological choices that have been made.
Particular attention must be given in the achievement of the alignment of the target compared with the laser
beams: it must be positioned at the center of the target chamber with a precision better than fifty micrometers rms. The
quality of this alignment must be guaranteed in order to ensure the success of the physics experiments performed on the
We are presenting the device that has been devised to reach this objective: the "Système de Visualisation de
Cible" (SYVIC) or target viewing system. This device is made of two optical visors set on the target chamber, associated
with a complicated three-dimensional reconstruction algorithm. It permits to position an object at the center of the
chamber, rapidly and with the required orientation. It also makes possible the alignment of all the plasma diagnostics,
mounted on the chamber wall in order to study the plasma created by the laser-matter interaction.
The first plasma experiment using the SYVIC alignment device took place at the beginning of 2007 with a
specific target. Doing so we qualified the accuracy of this device and its implementation on LIL.
Streak cameras and framing cameras used for studying single shot laser created plasmas at LIL and soon at LMJ need to be regularly controlled to assure a good operating system. This poster presents the laboratories that have been set up at CEA-CESTA to overcome this task. To cover the entire spectral domain required, many sources have been designed. First, AZUR laboratory is supposed to deliver three measurements ways equipped with laser sources for static and dynamic visible detectors control. Second, CADENCE laboratory is ought to test temporal resolution in UV domain by delivering laser ps pulse train. X-ray cameras are then calibrated by replacing CsI photocathodes with Pd photocathodes sensitive in UV. Finally, STATIX laboratory aims at controlling X-ray streak and framing cameras in static regime with several continuous X-ray sources. Properties as linearity, homogeneity, sensitivity and temporal response are going to be measured to guaranty diagnostics performances on LIL plasma physics shots.