Evaluation of Scattered Radiation Emitted From Cargo X-Ray Scanner on Occupational Dose of Operator

Baggage and cargo x-ray scanners are used at airports to check for passenger baggage and cargo to identify if there is any illegal goods or hazardous materials such as explosives or weaponries. The scanners are designed for security measures to screen baggage and medium to large cargo for border operation, critical infrastructure and economic activities. The purpose of the study is to assess the value of backscattered radiation produced by the x-ray scanner machine toward operators handling the scanners at several operational locations. Three X-ray scanners involved in this study include Model A and B with dual generator 180 kilovolt (kV) and Model C with dual generator which operates at 200 kV. Assessment done at several points around the scanners that are accessible during scanning and at Entry and Exit position of scanners tunnel. The tunnel of all scanners are equipped with shielding curtains to reduce the scattered radiation and also to prevent operators or the public from entering the tunnel. It was observed that, the highest radiation leakage dose rate from the accessible outer surface of each scanner models were at 5 cm from entrance Model A location K (1.270 μSv/h), exit-end Model B location N (1.540 μSv/h) and opposite operator-side Model C location G (0.488 μSv/h). Operator working for 40 hour per week, 50 week per year, radiation leakage dose rate measured at 5 cm from each scanner estimated to give occupational accumulative dose of 2.54 mSv/y (Model A), 3.08 mSv/y (Model B) and 0.976 mSv/y. The radiation dose levels during normal operation of the scanners are far below permissible dose limits for operators even considering full workload. (author)