This paper describes the synchronisation system under development on the Laser Mégajoule (LMJ) in order to
synchronize the laser quads on the target to better than 40ps rms. Our architecture is based on a Timing System (TS)
which delivers trigger signals with jitter down to 15ps rms coupled with an ultra precision timing system with 5ps rms
jitter. In addition to TS, a sensor placed at the target chamber center measures the arrival times of the 3ω nano joule laser
pulses generated by front end shots.
This paper describes the alignment system developed on the Laser Mégajoule facility, allowing to focus the laser beams
and to point the plasma diagnostics on the target. After an overview of the main laser components and alignment
architecture, we detail some major equipments as the 6 tele-microscopes used to align the target, the continuous phase
plate within the final optics assembly, the plasma diagnostic green pointer and the common reference which is the
cornerstone of the chamber center alignment. Finally we present some results obtained on the telemicroscope prototype
and a photometric prototype of the common reference. The expected performance of the alignment system will also be
Proc. SPIE. 7797, Optics and Photonics for Information Processing IV
KEYWORDS: Beam splitters, Image processing, Laser development, Amplifiers, Near field, Data processing, Photonics, Acquisition tracking and pointing, Current controlled current source, Picture Archiving and Communication System
The laser Megajoule (LMJ) project was launched in 1995 by the French Atomic Energy Commission and is aimed at developing a facility to achieve inertial confinement fusion. The LMJ architecture is based on 176 laser beamlines. To provide these 176 high-powered beams when required for subsequent operations, one of the main issues consists in reliably aligning the laser amplifier sections. This paper provides an overview of the image processing techniques developed to identify and measure the beam centering and pointing directions. These techniques have been developed and tested thoroughly against sets of up to 450 images representing both nominal and extreme conditions acquired during the initiation and power rising of the Laser Integration Line (LIL). This facility is fully consistent with the LMJ requirements, a complete laser chain with 4 beamlines. After presenting the basic design principles, we focus on the demonstrated performances measured.