Development of a Neutron POD Spectrometer

Los Alamos National Laboratory has a long history of research, development, test and evaluation, implementation, and installation of radiation detection equipment. The Nuclear Nonproliferation Division has done so in support of domestic and international safeguards, emergency response, nondestructive analysis, and criticality safety. One of the systems that we have developed and deployed for use in the field is the NPOD-III. The system is designed to perform correlated neutron measurements coupled with totals neutron counting, multiplicity, Feynman variance-to-mean, and Rossi-alpha analyses to determine the mass, multiplication, and alpha-n ratio, but many more capabilities have yet to be explored. We are developing an algorithm and determining the applicability of using the current design as a low-resolution neutron spectrometer, that may differentiate between different impurities present with alpha emitting materials. We are initially focusing on well-known lO-g PU02 standards that contain specific impurities. In addition we will be comparing other sources that have different chemical forms and impurity contents. A brief description of the detector, experimental constraints, and experimental results will be presented.