Advanced Plastic Scintillators for Nuclear Non-Proliferation Monitoring

The proliferation of weapons of mass destruction (WMD) is a serious threat. Preventing the spread of these nuclear weapons has reached a state of heightened urgency in recent years. Neutron detection is an important component of the overall detection techniques used in identifying WMDs. At present, there is need for an efficient detection system that would allow neutron detection with the ability to discriminate gamma from neutron events. Gamma discrimination is critical because gamma rays are a common background during WMD monitoring. Unfortunately, none of the available neutron detection technologies satisfy all of these requirements. Recent research at RMD has focused on novel plastic scintillators that can provide neutron/gamma pulse shape discrimination (PSD) capability. The goal of the proposed effort is to undertake a systematic investigation of novel plastic scintillators in order to optimize and advance the fast-neutron detection technology. To achieve this goal, the first step will be to tune the compositions including the monomers and additives as well as the optical emitters. Polymerization conditions will be examined to produce high quality plastic scintillators. Subsequently, we will evaluate their scintillation properties. Fast-neutron spectroscopy will be performed. Finally, neutron-gamma PSD studies will be carried out. The research work in the Phase I was focused on the following main areas: (i) fabrication of novel plastic scintillators, (ii) characterization of their scintillation as well as neutron detection properties, and (iii) investigation of neutron/gamma PSD. The research work in the Phase II will focus on the following five areas: (1) purification of monomers to improve the scintillation properties of the plastic scintillators, (2) fabrication of larger plastic scintillators of up to 16x4x4, (3) characterization of their scintillation properties, (4) investigation of neutron/gamma PSD, and (5) construction and evaluation of prototype detector systems. Commercial Applications and Other Benefits: The proposed detector technology will be very promising for nuclear non-proliferation. It will also be applicable to neutron imaging systems, astronomy, and non-destructive testing.