Wyniki wyszukiwania - BazTech

1

Study of a Compton backscattering wall defects detection device using the Monte Carlo method

Qin Xuan, Yang Jianbo, Du Zhengcong, Xu Jie, Li Rui, Li Hui, Liu Qi

Nukleonika

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2023

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Vol. 68, No. 2

57--63

EN

In view of the shortcomings of traditional wall defect detection methods, such as small detection range, poor accuracy, non-portable device, and so on, a wall defects detection device based on Compton backscattering technology is designed by Monte Carlo method, which is mainly used to detect the size and location information of defects in concrete walls. It mainly consists of two parts, the source container and the detection system: first, through the simulation and analysis of the parameters such as the receiving angle of thebackscattered particles and the rear collimating material of the detector, the influence of the fluorescent X-ray peak of the detector collimating material on the backscattered particle counts is eliminated and the detected error is reduced; second, the ring array detector design, compared with single array detector and surface array detector, can facilitate real-time detection of defect orientation, expanding the single scan range and improving the detection efficiency. After simulation and comparative analysis, the relevant optimal parameters are obtained: the object is detected using a Cs-137 γ-ray source with an activity of 6 mCi, and a ring detector consisting of four 0.5-inch cube-shaped CsI scintillator detectors is placed at 150° to receive the backscattered photons. The simulation analysis using the Monte Carlo FLUKA program showed that the maximum depth of wall defect detection is 8 cm, the maximum error fl uctuation range of defect depth and thickness is ±1 cm, the overall device weight is <20 kg, and the measurement time is <5 min.

2

Research on dose correction method of vehicle-borne environmental radiation measurement equipment

Xu Jie, Ren Jizhou, Yang Jianbo, Fan Jiawen, Li Rui, Li Hui, Huang Weiqi, Yuan Biao

Nukleonika

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2021

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Vol. 66, No. 3

103--110

EN

This study establishes a near-ground reference radiation field based on typical radionuclides of the Fukushima accident in response to the need for vehicle-borne environmental radiation measurement equipment that can accurately evaluate the environmental dose of nuclear accidents. The Monte Carlo code FLUKA is used to study the environmental dose of such equipment in the early and mid-late reference radiation fields of nuclear accidents. Results of the air dose rate at 1 m above the ground were corrected to eliminate data difference between diverse measurement platforms. Simulation results show that t he dose correction factor (CF) fluctuates at approximately 0.8813 in the early reference radiation field and at approximately 0.6711 in the mid-late reference radiation field . This deviation of the dose CF in the early and mid-late reference radiation field s is within 2% and is not affected by the change in detector position. This research can be applied to obtain more accurate measurement of an ambient dose in the near-ground radiation field and support the vehicle-borne environmental radiation measurement technology.

3

Fluka simulation of PGNAA system for determining heavy metal pollution in the soil sample

Zhang Can, Yang Jianbo, Li Rui, Qiao Yujie, Zhang Xu, Xu Jie

Nukleonika

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2020

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Vol. 65, No. 1

13--17

EN

This study presented a self-designed prompt gamma neutron activation analysis (PGNAA) model and used Fluka simulation to simulate the heavy metals (Mn, Cu, Hg, Ni, Cr, Pb) in soil samples. The relationship between the prompt gamma-ray yield of each heavy metal and soil thickness, content of heavy metals in the soil, and source distance was obtained. Simulation results show that the prompt gamma-ray yield of each heavy metal increases with the increase in soil thickness and reaches saturation at 18 cm. The greater the proportion of heavy metals in the soil, the greater the prompt gamma-ray yield. The highest content is approximately 3%, and the change in distance between the neutron source and soil sample does not affect the prompt gamma-ray yield of heavy metals.