Progress of an optical calibration system for nuclear imaging

The Nuclear Imaging System (NIS) is a diagnostic suite at the National Ignition Facility (NIF) used to create reconstructions of inertial confinement fusion (ICF) implosions. The NIS contains fast-gated, intensified cameras coupled to scintillators that record penumbral and pinhole -projected images of primary and down -scattered neutrons and gammarays to allow tomographic reconstruction of the compressed fuel, shell, and structure of ICF plasma during the fusion burn. Producing successful reconstructions requires the optical system to be fully calibrated by correcting for image warping, registering the cameras to each other, and characterizing the sensitivity variations across the field of view. This has historically been performed by using two neutron -producing shots without the pinhole aperture, thus sacrificing data from those shots. We present the progress of the development of an optical calibration system that will use an LED light panel for illumination in place of some neutron-producing shots to enable the necessary calibrations at regular intervals with a reduction in data loss for the NIS.