Research On Identification System Of Hazardous Chemical Based On PGNAA Technology

Chemical weapons left over from the war have showed a great threat to the lives and property of the people.How to identify the type of chemical warfare agents accurately and effectively is of great significance for the later processing.Among the existing chemical weapons identification technologies,the Prompt Gamma-ray Neutron Activation Analysis(PGNAA)technology has unique advantages by analyzing the gamma-ray spectrum generated by the activation between neutron and samples.Based on actual needs,device was designed in this work based on PGNAA technology,and 8 samples were carried out in this experimental device.Firstly,based on the D-T neutron generator and high-purity germanium(HPGe)detector,the structure of the device was optimized by using the signal-to-noise ratio optimization method.The source of the signal and noise in the device was clarified.MCNP code was used to optimize this device,including reflector,moderator and the shielding.The aim is to increase the signal while reducing the interference of the noise.And also the dose was calculated in the research.Secondly,a measurement device was established for identifying the chemical weapons.And the measurement was performed by using an HPGe detector with a relative efficiency of 30%.The results showed that it can effectively analyze the presence of hydrogen,chlorine,phosphorus,nitrogen and other elements in the sample,but the detection of sulfur and fluorine was not effective.In order to make full use of the effective elements information in the samples,some improvements have been made to the detection system.A combination of high-efficiency HPGe and BGO detector was used to detect more elements.Finally,the classification of simulated samples was realized by the logic tree discrimination process.