Neutron source moderation technique for PFTNA landmine detection

Pulsed fast/thermal neutron analysis (PFTNA) is an advanced bulk technique for non-destructive elemental characterization, which plays an important role of confirmation sensor in demining activities, but it has a drawback in the detection speed of nitrogen. For improving the detection speed of nitrogen in the object under interrogation in PFTNA landmine identification experiment, a brand new graphite moderator designed using Mont-Carlo method was introduced to the pulsed D-T neutron generator. The simulation results indicated that the adoption of the moderator can largely increase the thermal-neutron flux between pulses, and then increase the detection speed of nitrogen. The theoretical enhancements brought by the moderator was validated by relevant experiment, and the verification data tallied well with the simulation result, which demonstrated the adoption of graphite moderator can largely improve the detection speed of nitrogen in PFTNA countermine experiment. (authors)