A large-format imaging optics system for fast neutron radiography

As part of the ongoing development of fast neutron imaging technology for national security applications at LLNL, a large-format imaging optics system is being designed and built. The system will be used to acquire radiographic images of heavily-shielded low-Z objects irradiated by ~10 MeV neutrons and is expected to have an ultimate spatial resolution ~1 mm (FWHM). It is comprised of a 65 cm times 65 cm plastic scintillator (e.g. BC-408), an aluminized front-surface turning mirror and a fast (~f/1.25) optical lens coupled to a CCD camera body with a cryo-cooled, back-illuminated 4096 times 4096 (15 mum) pixel sensor. The lens and camera were developed and purchased from vendors and system integration is being done at LLNL. A description of the overall system and its projected performance characteristics shall be presented.