某设备所致脉冲X射线辐射场测量与防护评价

目的了解某设备实验条件下不同位置脉冲X射线电离辐射水平,提出适当的防护建议。方法采用热释光测量方法,分别在设备舱周围不同方向不同距离布放热释光剂量计,累积一定数量脉冲辐射后进行测量;采用电离室型X、γ剂量率仪(FJ-347A)实时测量工作状态下不同距离处电离辐射剂量率水平。依据《电离辐射防护与辐射源安全基本标准》(GB18871-2002)规定的职业照射人员和公众个人剂量限值提出不同工作位辐射防护建议。结果热释光剂量计累计接收3 000个脉冲辐射,设备舱外壁0.01~8.98 mGy,顶部0.01~15.67 mGy,距外壁1~12 m之间0.01~2.18 mGy,工作位0 mGy。工作状态下,X射线剂量率仪测得距设备舱外侧壁1~20 m之间空气比释动能率范围0.26~16 mGy/h。结论热释光剂量计、电离室型剂量率仪测量结果基本一致,说明两种方法均可用于脉冲X射线测量;工作状态下设备舱外近距离处辐射剂量率较高,可通过采取防护措施或者限制人员工作量以满足辐射防护要求。

Measurement and protection evaluation of pulsed X-ray radiation field induced by a certain equipment

Objective To investigate the ionizing radiation levels of pulsed X-ray at different positions under experimental conditions of a certain equipment, and to propose appropriate protective suggestions.Methods Thermoluminescence measurement method is adopted. Thermoluminescence dosimeters were set up in different directions and distances around the equipment cabin, and were measured after a certain amount of pulsed radiation was accumulated. X-ray and gamma ray ionizing chamber dosimeter (FJ-347A) was used for real-time measurement of the dose rate of ionizing radiation at different distances. Recommendations on radiation protection at different working positions were made according to the individual dose limits for occupational exposure personnel and members of the public stipulated in the “Basic standards for protection against ionizing radiation and for the safety of radiation sources” (GB 18871—2002).Results Thermoluminescence dosimeters received 3000 radiation pulses accumulatively. The dose received by the thermoluminescence dosimeters on the outside wall of the equipment cabin ranged from 0.01 mGy to 8.98 mGy, the roof ranged from 0.01 mGy to 15.67 mGy, 1～12 meters from the outside wall ranged from 0.01 mGy to 2.18 mGy, and work stations was 0 mGy. Under the working condition, the range of air kerma rate measured by the X-ray dosimeter between 1～20 meters from the outside wall of the equipment cabin was 0.26～16 mGy/h.Conclusion The results of thermoluminescence dosimeters and ionizing chamber dosimeter are basically consistent, indicating that both methods can be used for pulsed X-ray measurement. In working condition, the radiation dose rates in short distance outside the cabin of the equipment are relatively high. Radiation protection requirements can be met by taking safety protection measures or limiting the workload of personnel.