Simulation Study Of Prompt Gamma Activation Imaging Technology Based On The Thermal Neutron

Radiation imaging has been widely used in the medical,security,and other fields.But the traditional imaging technology only can obtain the profile and density information of sample,can't get the inner elements distribution information of sample.Prompt gamma activation imaging(PGAI)is based on the prompt gamma ray neutron activation analysis(PGNAA).PGAI not only can measure the inner element of sample in quantitatively and qualitative,but also obtain the 3D distribution of elements,compared with the traditional neutron imaging,and make up the blind spot.But the PGAI was carried out by cold neutron source in the reactor,and its application was limited in greatly.In face of the problem,in this paper,we analysis the PGAI technology under the thermal neutron based on D-D neutron generator in this paper.Design and optimize the PGAI measurement platform by the Monte Carlo software,measure three kinds of samples and analyze the interference factors of the measurement result.The main contents are as follows: 1)The PGAI measurement platform based on the D-D neutron generator was developed.The moderator,reflector,collimator,shield were designed and optimized by the Monte Carlo software.And choose the appropriate gamma ray detector,Design and optimize the collimator of the detector.2)Reconstruct the image by the simulated data,and analyze the physical mechanism of the low measurement accuracy of results.The main influence factors include: the neutron self-absorption,neutron scattering and ?-ray attenuation.Firstly,establish correction model by the neutron transport theory.In order to get neutron flux of each volume accurately,establish correction model by MCNP,and get a good correction result.According to the laws of the gamma ray attenuation the gamma ray correction model is established,the response of each location of the inner element sample is almost unanimously,improve the quality of the reconstruction image further.And analyze the effect of the size of volume for the results at the same time.