基于三角圆筒铅屏蔽NaI探测器的放射源定位研究

随着放射源和放射装置的广泛应用,放射源事故的发生概率不断增大。因此,一旦发现放射源丢失,如何尽快将其定位并安全找回尤为重要。本文设计了一种三角圆筒铅屏蔽的NaI探测器,用于放射源的定位探测。实验研究了测量时间、铅屏蔽厚度、源与探测器间距、伽马射线能量等因素对放射源定位的影响。结果表明:对于137 Cs源,在空气吸收剂量率≥0.028μGy/h处,定位平均角度偏差≤1.24°;对于60 Co源,在空气吸收剂量率0.4μGy/h处,测量的平均角度偏差为1.16°;对于距离约1.5 m的9.25×105 Bq 137 Cs源,定位偏差约为0.097m。

Study of Radioactive Source Localization Based on Triangular Cylindrical Lead Shield NaI Detector

With the wide spread applications of radioactive sources and radiation devices , the probability of radiation accidents caused by sources becomes larger .T herefore ,how to locate and safely find those radioactive sources ,w hich had been lost is quite impor-tant .In this paper ,a triangular cylindrical lead shield NaI detector was designed to locate the radioactive source .In the experiment ,the influences of the measuring time , the thickness of the lead shield ,the distance between the radioactive source and the detector ,and the energy of the gamma ray on the location accuracy of the radioactive source were studied .The experimental results show that for 137Cs source ,when the air absorbed dose rate is ≥0.028 μGy/h ,the average angle deviation from air-sorption is≤1.24° .For 60Co source ,when the air absorbed dose rate is 0.4 μGy/h ,the average angle measurement deviation is 1.16° .For 9.25 × 105 Bq 137 Cs source ,position deviation within the distance of 1.5 m is about 0.097 m .