Advances in imaging fission neutrons with a neutron scatter camera

Special nuclear material (SNM) emits high energy radiation during active and passive interrogation. This radiation can be imaged thus allowing visualization of shielded and/or smuggled SNM. Lower backgrounds and higher penetration through hi-Z materials make neutrons the preferred detectable in many scenarios. We have developed a neutron scatter camera that directly images fast fission neutrons from SNM sources while simultaneously measuring energy spectra. We have made many significant advances in the design and implementation of such instruments leading to an over 30 fold improvement in sensitivity. We will present results from our detector including analysis techniques that we have developed for neutron imaging and particle discrimination techniques. We will discuss camera calibration and performance under realistic threat detection scenarios, and future prospects in this field.