From Event: SPIE LASE, 2023
The National Ignition Facility (NIF) employs 192 laser beams to achieve inertial confinement fusion by irradiating a mm scale fusion target. Automatic alignment (AA) image processing algorithms are used to align 192 beams to the NIF target chamber center. Cameras placed along the beam path supply the images that are analyzed by AA algorithms to provide beam location and alignment information. NIF has the capability of using beam-specific database parameters. This allows beam line images to be processed using optimized algorithms tailored to individual beam alignment needs. For a given segment of alignment in the NIF beam path, 192 different versions of the algorithm can be run simply by changing data base parameters. This capability is vital to alignment precision in a system as complex and mature as NIF. Since optical components and devices age, laser parameters and beam alignment quality can and do change. Constant beam-by-beam monitoring of alignment performance is needed in order to mitigate any issues caused by such changes. The objective of this work is to evaluate how periodic AA algorithm beam parameter changes might better maintain alignment requirements over time in the NIF facility. We show examples from final optics assembly (FOA) and harmonic generator (THG, SHG) loops.
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Abdul A. S. Awwal, Richard Leach, Roger Lowe-Webb, and Vicki Miller Kamm, "Beam-line parameter image processing optimization and maintenance for beam alignment in the National Ignition Facility," Proc. SPIE 12401, High Power Lasers for Fusion Research VII, 1240107 (Presented at SPIE LASE: February 01, 2023; Published: 14 March 2023); https://doi.org/10.1117/12.2657715.