The Detection Of Shallow Buried Explosives In The Soil By PGNAA Technique

Millions of landmines remaining from past conflicts have produced serious humanitarian problems in many countries,the detection of landmines which left over after the wars has become a focus of the international community.It has become a very important method that the prompt gamma-ray neutron activation analysis(PGNAA)technique was applied to detect the landmine in the existing detection technologies,due to the detection of the landmines' element and its low false alarm rate compared with other detection technology.This study designed two kinds of landmine detection devices based on the PGNAA technology and a method was proposed to detect the landmines' position based on the TNA device according to the actual demand.Firstly,a thermal neutron analysis(TNA)detection device was developed using a 252 Cf neutron source to determine the existence of the landmine by detecting the nitrogen according to the characteristics of the explosives' higher nitrogen content.And the moderator,reflector,shield were designed and optimized by the Monte Carlo method with the design criteria of the signal strength.Secondly,a fast/thermal neutron analysis(FNA/TNA)detection device was developed based on the electric controlled D-T neutron generator to determine the existence of the landmine by detecting the nitrogen and the abnormal content of carbon and oxygen,and the moderator,reflector,composite shield were designed for high-energy neutrons to meet the requirements of fast neutron analysis and thermal neutron analysis at the same time.Finally,when the TNA device scanning for landmines,the three detectors will have different response of nitrogen element.A method was proposed in this study to detect the precise location of landmine and the Monte Carlo simulation result shows that this method can effectively detect the position of the landmine.