工业脉冲X射线发生装置放射防护检测与评价方法研究

Discussion and Research on Radiation Protection Detection Methods and Evaluation Methods of Industrial Pulsed X-Ray Generators

目的探讨利用热释光剂量计对工业脉冲X射线发生装置进行放射防护检测与评价的可行性。方法分别用热释光剂量计和AT1123型X/γ辐射剂量率仪测量脉冲X射线发生装置的辐射剂量,通过对测量结果的分析和比较验证热释光剂量计测量脉冲X射线的有效性,通过对周围环境中年累积剂量的估算来评价试验人员和公众的受照剂量是否满足辐射防护要求。结果1号脉冲X射线发生装置曝光4次,2号脉冲X射线发生装置曝光10次,热释光法测得不同距离处的累积剂量符合距离平方反比衰减规律,实际检测结果与理论推算值较为吻合。两个X射线发生装置现有的工作负荷下,工作人员和公众的年累积剂量均在辐射防护控制目标值内。结论热释光法得出检测结果与理论推算值较为吻合,能够满足工业脉冲X射线发生装置放射防护检测需求。

Objective The feasibility of using thermoluminescence dosimeter for radiation protection detection and evaluation of industrial pulsed X-ray generator is discussed.Methods Arrange thermoluminescence dosimeters and AT1123 X/γradiation dose rate meters at key points in the workplace of the pulsed X-ray generator.Trigger the exposure of the pulsed X-ray generator,and read the test results of the AT1123 X/γradiation dose rate meters on site.The thermoluminescence dosimeters are taken back to the laboratory for reading.Result By thermoluminescence method,the cumulative doses of the no.1 pulsed X-ray generator are 620.9μSv,71.3μSv and 22.5μSv at 1 m,3 m and 5.6 m from the center of the radiation beam axis,respectively.The highest cumulative dose is 199.5μSv at 1.0 m on the left and right sides of the pulsed X-ray tube(near the target)and 14.6μSv at 1 m behind the tube.The cumulative dose of 4 exposures outside the shielding wall is between 8.2μSv and 1.0μSv.The radiation dose distribution around the X-ray tube of no.2 pulsed X-ray generator is basically consistent with that of No.1 generator.AT1123 X/γradiation dose rate meter shows that the dose equivalent rate is 18.8 mSv/h around the center 1 m of the beam axis at the instant of exposure.Conclusion The detection results obtained by the thermoluminescence method are in good agreement with the theoretically calculated values,which can meet the requirements of radiation protection testing for industrial pulse X-ray generator.The test result evaluation method adopted in this paper can give a quantitative evaluation conclusion on the radiation protection effect of the pulse X-ray generator workplace,and the evaluation method has certain feasibility.