Design and implementation of a gated-laser entrance hole imaging diagnostic (G-LEH-1) at NIF

Gated x-ray images through the laser entrance hole (LEH) of a hohlraum can provide critical information for ICF experiments at the National Ignition Facility (NIF), such as the size of the LEH vs time, the growth of the gold bubble 1 , and the change in the brightness of inner beam spots due to time-varying cross beam energy transfer 2 . Incorporating a high-speed multi-frame CMOS x-ray imager developed by Sandia National Laboratories 3,4 into the existing Static X-ray Imager (SXI) diagnostic5 at NIF, the new Gated LEH Imager #1 (G-LEH-1) diagnostic is capable of capturing two to four LEH images per shot on its 1024x448 pixel photo detector array, with integration times as low as 2 ns per frame. The design of this diagnostic and its implementation on NIF will be presented.