Muon scattering tomography technology can be of great use in detecting nuclear materials under excellent shielding, thus distinguishing itself from traditional radiography technology. In this study, we firstly introduced the principle of this radiography technology and the rationale of PoCA algorithm used in image reconstruction. Then several experimental models were constructed with the help of Geant4 toolkit, and several sets of simulation experiments were carried out to test the performance of this technology with PoCA algorithm. In order to improve the imaging quality, we designed experiments to find out the cause of distorted image, and then proposed an optimization method. Finally, a quantity was created to present the imaging quality, and several experiments were carried out to validate the effect of this optimization method. The result showed that this method can significantly improve the performance of this algorithm.

With the development of nuclear industry, nuclear facilities have accumulated a large amount of pending nuclear waste during operation. Usually, they are stored in a closed container, and their physical and chemical forms are complicated and unevenly distributed. γ-ray 3D scanning detection and analysis system using non-destructive analysis of γ-ray analysis method to achieve a closed container of radionuclide recognition, positioning, quantitative measurement and analysis. The system has broad application prospects in the fields of nuclear safety, nuclear material control and accounting, radioactive recyclables and non-destructive measurement of nuclear waste. γ-ray 3D scanning detection and analysis technology is a comprehensive high-tech integrated nuclear science, nuclear radiation detection, radiation imaging, image processing, mechanical design, automatic control, computer technology and other disciplines.

Segmented Gamma Scanner (SGS) is a commonly used nondestructive testing (Non-Destructive Assay NDA) method. SGS uses radial rotation, axial segmentation, segmented scanning of the non-uniform sample of the uniform treatment, making it possible to accurately measure the radioactivity on each segment and is currently widely used in the field of nuclear material management. This paper introduces a self-designed SGS measuring device and uses this device to perform a large number of scanning experiments on different measurement objects in the laboratory. It also studied the detection performance, stability and SGS method of different objects the accuracy of the measurement results.

Gamma camera imaging technology is a non-destructive passive radiation imaging technology, which can quickly find the unknown source location, search the exact number of radioactive sources and relative intensity. Therefore, it is very important and widely used in the fields of effective regulation of radioactive sources, handling of various nuclear emergencies, nuclear arms control and other fields. In the practical application of gamma camera, it often faces the imaging difference caused by the difference of radiation source intensity, detection time and detection distance. It is helpful to study the change of imaging characteristics under different experimental conditions for the practical application of gamma camera under different scenes. In this paper, the structure and imaging principle of gamma camera are analyzed in detail. Using the Cartogam portable gamma camera, a set of comparative experiments are carried out to study the time characteristics, distance characteristics and source intensity characteristics of the gamma camera. The results show that the imaging quality of gamma camera is positively correlated with the time source intensity, negatively correlated with the distance. For a milliCurie source, the gamma camera has very good fast-position resolution at a distance of 1 meter from the radioactive source and can form a more complete hot spot image within 5 minutes. When the distance becomes larger, the radioactive source needs at least 20 minutes to form a more accurate hot spot image. The hot spot is no longer as complete as a concentric circle structure, but can achieve precise positioning. For a strong source of more than ten milliCurie, immediate imaging within two minutes can be basically achieved within two meters. Under multi-source conditions, when the source intensities differ greatly and the distance between sources is relatively close, the detection of weak source can not be achieved by increasing the measurement time. However, by observing the counting images in a short period of time, the possibility of existence of a weak source can be deduced. Therefore, in the practical application of the gamma camera, it is necessary to constantly adjust its imaging conditions to ensure the detection of weak source verification. In this paper, the Monte Carlo model of gamma camera is set up to simulate the imaging. Compared with the actual imaging hot spots, the simulated images can correctly reflect the hot spot graph’s level distribution, which has the value of further research.

The paper constructs the model of nuclear materials and fast neutron multiplicity counter, and obtains the mass of nuclear materials by utilizing the equation of fast neutron multiplicity. Via GEANT4 tool kit, the paper obtains the simulated results which are identical well to the results calculated by the equation. This indicates the validity and feasibility of computer simulation of fast neutron multiplicity analytical method and lays the foundation of the design and application of fast neutron multiplicity counter.