Derivation of preliminary specifications for transmitted wavefront and surface roughness for large optics used in inertial confinement fusion
- Lawrence Livermore National Lab., CA (United States)
- CEA-DAM-Centre d`etudes de Limeil-Valenton, Villeneuve St. Georges (France)
In preparation for beginning the design of the Nation Ignition Facility (NIF) in the United States and the Laser Mega-Joule (LMJ) in France, the authors are in the process of deriving new specifications for the large optics required for these facilities. They are currently being evaluated through modeling and experimentation. These specifications will be ready for general release by the end of the year. Traditionally, specifications for transmitted wavefront and surface roughness of large ICF optics have been based on parameters which were easily measured during the early 1980`s, such as peak-to-valley wavefront error (PV) and root-mean-square (RMS) surface roughness, as well as wavefront gradients in terms of waves per cm. For the NIF and LMJ laser systems, the authors have availed themselves of advances in metrology and interferometry and an enhanced understanding of laser system performance to derive specifications which are based on power spectral densities (PSD`s.) Such requirements can more accurately reflect the requirements of the laser system for minimizing the amplitude of mid and high-spatial frequency surface and transmitted wavefront errors, while not over constraining the fabrication in terms of low spatial frequencies, such as residual coma or astigmatism, which are typically of a very large amplitude compared to periodic errors. In order to study the effect of changes in individual component tolerances, it is most useful to have a model capable of simulating real behavior. The basis of this model is discussed in this paper, outlining the general approach to the ``theoretical`` study of ICF optics specifications, and an indication of the type of specification to be expected will be shown, based upon existing ICF laser optics.
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 234198
- Report Number(s):
- CONF-9505264-; ISBN 0-8194-1997-4; TRN: IM9624%%239
- Resource Relation:
- Conference: 1. annual solid-state lasers for application to inertial confinement fusion meeting, Monterey, CA (United States), 30 May - 2 Jun 1995; Other Information: PBD: 1995; Related Information: Is Part Of First annual international conference on solid state lasers for application to inertial confinement fusion; Andre, M.; Powell, H.T. [eds.]; PB: 797 p.; Proceedings/SPIE, Volume 2633
- Country of Publication:
- United States
- Language:
- English
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