固体^(219)Rn源的γ能谱法放射性纯度检验  

Determination of Radioactivity Purity of Solid ^(219)Rn Source byγ-ray Spectrometry

作　　者：唐泉[1] 安小刚[1] 丘寿康[1] 

机构地区：[1]南华大学核科学技术学院,湖南衡阳421001

出　　处：《原子能科学技术》2014年第12期2381-2386,共6页Atomic Energy Science and Technology

基　　金：国家自然科学基金资助项目(11275094)

摘　　要：对利用从铀矿石中提取得到的227Ac制备的固体219Rn源进行了γ能谱分析,确定了227Ac的4个子体核素227Th、223 Ra、219Rn和211 Bi的活度,并分析了能对219Rn造成干扰的222 Rn、220Rn母体核素226 Ra、224 Ra的活度。待227 c及其子体达到放射性平衡后,通过测量227Th的235.97、256.25keV,223 Ra的154.21keV,219Rn的401.81keV,211Bi的351.059keV共5条γ射线,最终确定固体219Rn源中227Th、223 Ra、219Rn和211Bi的活度为(1 069±3)、(1 079±5)、(1 095±13)、(1 096±14)和(11 089±4)Bq,固体219Rn源的平均活度为(1 093±8)Bq;通过测量224 Ra子体212Pb的238.632keV、208 Tl的583.191keVγ射线以及226 Ra子体214 Bi的609.312、1 120.287keVγ射线得到226 Ra与224 Ra的平均活度分别为5.12Bq及0.433Bq,远低于固体219Rn源的平均活度,说明固体219Rn源放射性纯度较高。以上结果表明,此源有望制成标准固体219Rn源以用于延迟符合法测223 Ra、227Ac装置的刻度。Radioactivity purity of the solid 219Rn source made using 227Ac extracted from uranium ore were determined byγ-spectrometry.The activities of 227Th,223 Ra,219Rn and 211 Bi produced by the decay of 227Ac and the contents of 226 Ra,224 Ra which generates222 Rn,220Rn to affect the purity of actinide in this source were analyzed after 227 c in radioactive equilibrium with its daughter nuclides.The γ-ray energy used for the determination of these daughter nuclides of 227 c are 235.97,256.25 keV for 227Th,154.21 keV for 223 Ra,401.81 keV for 219Rn,and 351.059 keV for 211 Bi.Through the analysis,the results are acquired that their activities are（1 069±3）,（1 079±5）,（1 095±13）,（1 096±14）and（11 089±4）Bq respectively,and the average activity of solid 219Rn source is（1 093±8）Bq.The activities of 226 Ra and 224 Ra in this source are5.12 Bq and 0.433 Bq respectively by theγ-ray energy as follows：238.632 keV of212Pb,583.191 keV of 208 Tl for 224 Ra,and 609.312,1 120.287 keV of 214 Bi for 226 Ra,as they are all far below（1 093±8）Bq,so the radioactivity purity of the solid 219Rn source is very high.The results show that the solid 219Rn source can be developed to the standards for the efficiency calibration of the delayed coincidence counting system.

关 键 词：Γ能谱法 固体^219Rn源 227Ac 延迟符合测量 

分 类 号：TL817.2[核科学技术—核技术及应用]