Airborne gamma radiation field simulation method based on finite element analysis

This paper presents a method for simulating an infinite radiation-contaminated field based on finite element analysis, which has been designed to meet the experimental requirements for unmanned airborne vehicle radiation detection in nuclear emergency scenarios. Based on the principle of radiation field superposition, the infinite surface sources are divided into finite elements, and an equivalent model is established with point sources and finite element surface sources. By arranging the finite point sources in accordance with the coordinate distribution calculated by the model, the response of the airborne radiation detector to the finite element surface sources and the corresponding point sources is consistent when the activities of the finite point sources and the corresponding finite element surface sources are identical. Based on the proposed equivalent model, an airborne gamma artificial radioactive field simulation device is designed, and physical validation experiments are carried out using two-dimensional and three-dimensional infinite surface sources. Two experimental results have showed that the maximum relative deviations between the infinite surface and the equivalent model in the full energy peak counts are 1.67 % and 2.62 %, respectively. The equivalent model proposed in this paper can accurately simulate nuclear radiation-contaminated fields with arbitrary activity and terrain distribution.