某市地铁2号线安检系统放射防护检测结果分析

Analysis on radiation monitoring of security system for metro line 2 in a city

目的了解某市地铁2号线X射线行李包检查系统(以下称为安检系统)放射防护的情况,为加强放射卫生管理工作提供技术支撑及基础资料。方法选取某市地铁2号线,共57台X射线安检系统,在距离其外表面5cm处进行防护检测其关注点的空气比释动能率。结果旅客通道、安检工作人员操作处、安检机的左右侧板和顶盖、取包处的检测值均与本底环境值差异无统计学意义(P>0.05)。安检机里面以及行李出入口铅帘处的检测结果高于本底,且差异有统计学意义(P<0.05),其中的行李包入口处在57台安检机中有1台的监测结果超过5μGy/h的限值要求,为6.7μGy/h,且该设备周围的平均空气比释动能率最大,为0.79μGy/h。安检系统里面的辐射量差别较大,不同安检系统或者同型号的安检系统之间都存在差别,最高值为5.4 m Gy/h,均值为0.4 m Gy/h。结论 X射线指示灯亮起时安检机入口和出口可能存在X射线泄漏,但对乘客、安检工作人员的辐射危害影响较小,建议加强地铁安检系统的放射防护管理;在安检机的选购方面也值得关注其性能。

Objective To grasp the status of radiological protection for X - ray luggage ：inspection system used in the Metro Line 2, and to provide technical support and basic data for radiological health management works. Methods A total of 57 sets of X - ray luggage inspection system were investigated. The air kerma rate at a distance of 5 cm from the outer surface was mo- nitored. Results The levels of air kerma rates in the passengers＇pathway, staffg working place, the left and right sides of pan- els, the top cover and the bag claim areas were the same as the background level. The radiation levels inside the system and the entrance or exit of the baggage were higher than the background （ P 〈 0.05 ）. The value （6.7 pμGy/h） at the entrance of 1 system was found to be higher than the limit of 5 pμGy/h, and the averaged value of 0.79 I.LμGy/h surrounding the system was also the maximum among the 57 sets of system. There was a big difference of air kerma rates inside different types or sets of the security inspection systems. The highest value was 5.4 mGy/h, and the mean value was 0.4 mGy/h. Conclusion There exists the X ray leakage at the entrance and exit of the security inspection system when the X - ray is on, but it has little radia- tion influence on the passengers and staff. However, the management of radiological protection for the security inspection sys- tem is still needed to be strengthened. Selection the security inspection system is also worthy of attention.