Thermal neutron analysis technology

This paper describes the application of thermal neutron analysis (TNA) to a variety of non-intrusive detection problems. TNA is based on the analysis of neutron capture gamma rays from particular elements which are indicative of the material of interest. TNA was developed for detection of concealed explosives in airline luggage during the late 1980's and is now being investigated and tested for new applications. These applications include detection of drugs in passenger luggage, detection of explosives and drugs in small packages, detection of liquid explosives in bottles, and detection of buried land mines and unexploded ordnance. For explosive, land mine and UXO detection, the TNA is based on the 10.8 MeV capture gamma ray from nitrogen, whose high density is uniquely characteristic of modern high explosives. For detection of drugs, the use of capture gamma ray signals from both hydrogen and chlorine (from hydrochloride drug salt) have been investigated, and a specific set of features based on these gamma ray signals selected for the detection algorithm. The research and test results of this wider application of TNA, carried out over the last year will be described.