Computed tomography with fast-neutron sources

Lawrence Livermore National Laboratory (LLNL) is near-completion of a quasi-monoenergetic neutron source for fastneutron imaging and computed tomography (CT). The source is expected to produce 10-MeV neutrons with an on-axis flux of ~1011 per second per steradian through a collimated aperture with a ~7-degree opening angle. The application for this source is imaging and CT of low-Z materials heavily shielded by high-Z materials. Fast-neutron imaging and CT is a non-destructive technique for very thick objects. We have radiographed a variety of objects using various sources of fast neutrons. We will discuss our CT reconstruction methods and results from these measurements. We will also discuss our results as they relate to our expectations of the near-complete neutron source at LLNL.