Abstract: The explosive detection system based on tagged neutron method was designed. The system used the ING-27 neutron generator and the LYSO γ detector for detection. The explosives were distinguished based on sequential probability ratio test (SPRT) method. The characteristic peaks of C,N, and O elements were analyzed and calculated in the measured γ energy spectrum data of milk powder, ammonium nitrate (AMM) and TNT simulators. The probability ratio results were compared with the corresponding thresholds ln A and ln B. The results show that the SPRT method can be applied to the explosive decision.

Key words: sequential probability ratio test (SPRT), explosive, energy spectrum, tagged neutron