Real-time, fast-neutron spectroscopy for source identification in mixed-field imaging applications

The need for radiation assessment in nuclear decommissioning and decontamination has led to the production of several gamma-ray imaging systems. Those currently in widespread use, rely solely on the gamma-ray field to obtain spatial information of radioactive sources. Recent advances in detector technology allow mixed radiation fields to be discriminated in real-time and thus to include neutron radiation in non-intrusive radiological evaluation. In this paper neutron energy deposition in an EJ-309 detector has been investigated for three different neutron sources showing they can be distinguished with relatively low exposure to a detector; making way for use in imaging applications. Imaging experiments were performed with americium-beryllium and californium allowing the sources to be identified individually. These sources were imaged simultaneously in close proximity and were distinguished using a least chi squared fit technique.