Precision diagnostic system enhancements and recommissioning for advanced laser beam characterization at the National Ignition Facility

Abstract

The Precision Diagnostic System (PDS) is an advanced set of laser diagnostic tools installed within the National Ignition Facility (NIF). It is capable of picking off a single, full aperture, 1053nm (1ω) beamline before the beam propagates to the target chamber and directing it to a suite of precision laser diagnostics. It was instrumental in validating the performance of the final optics 3Ω frequency conversion system design when NIF was built. The PDS has recently been recommissioned after more than a decade of non-use and enhanced to better understand laser performance limitations1 and to characterize underperforming beams. In addition to recommissioning existing diagnostics for calorimetry, power, wavefront, near-field and far-field imaging, new diagnostics have been added: two types of time-resolved near field imaging systems; higher resolution wavefront imaging; and a 1ω spectrometer. Additionally, the beam transport system was upgraded to allow PDS to select among four different 1ω beamlines to enable improved understanding of beam-to-beam variations. Two of these four beams are top-hemisphere beams, while two are bottom-hemisphere, with known performance variations. The results from NIF Shots with the new and recommissioned PDS diagnostic (spatial resolution, dynamic range, time gating, etc..) will be reviewed and data up to 14 kJ, 3.2 TW will be presented.