Neutron moderation for imaging of SNM

The use of a thermal neutron detection array comprised of boron straws, a ³He replacement technology, was embedded in a high density polyethylene (HDPE) neutron moderating array to investigate the possibility of one dimensional neutron source localization. The HDPE structure around the boron straw detectors was varied to identify the optimum background suppression and neutron source enhancement. Initial results have indicated that the use of a complex HDPE mask structure will provide a means to image non-moving source locations and is applicable to current portal monitor technologies that utilize other techniques for source presence identification and imaging when the source is moving.