National Ignition Facility (NIF) is the world’s most energetic laser system, capable of delivering over 1.8 MJ of energy at UV. After operating for over 10 years and working continuously to improve the damage resistance of the optics, there seems to be a disconnect between the offline measured damage performance of optics and the actual lifetime of an installed optic. Recently, we have discovered a source of laser-induced optic damage that originated from particles ejected from damage of a neighboring disposable optic. We were able to replicate this contamination-driven laser-induced damage experimentally in an offline facility and have developed a phenomenological model based on the results which includes particle generation, particle cleaning, and particle damage as a function of damage size as well as laser fluence. The model was able to accurately predict the multi-shot process of the offline experiment. Since then, we have used this model to predict online damage performance on NIF on a series of very high energy shots to test the validity of model with surprising results that shows the success of the model along with new features that will need to be address.
This work was performed under the auspices of the U. S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. (LLNL-ABS-745711)
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