Pages: 270-279

Authors: Yang Xu, Chen Luo, Yan Huang, Kebin Jia, Yuntao Liu, and Min Lin

Abstract

This article focuses on the in-situ calibration of area radiation monitors by examining changes in backscatter factors. A mobile X-ray irradiation device was developed, and a reference radiation level was established. Using the Monte Carlo method, an in-situ calibration measurement model was created to study backscatter factors at different distances and radiation field conditions for radiation qualities ranging from N-60~N-200. The accuracy of the simulation was verified, with a relative deviation between simulation and experimental results not exceeding ±4.7 %. In addition, the variation of the backscatter factors with different chamber-wall distances and wall materials was simulated. Results indicate that backscatter factors for all materials decrease as the chamber-wall distance increases. For conventional concrete, the maximum backscatter factor within the studied energy range did not exceed 1.35. It is important to note that for heavy concrete and lead, the presence of K absorption edges can result in a sudden increase in scattered radiation.

Key words: mobile X-ray device, in-situ calibration, air kerma, backscatter factor, Monte Carlo

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