Gamma能谱无源效率刻度方法在稀土样品放射性检测中的应用  

Application of γ Spectrometry Sourceless Efficiency Method in Measuring Radioactive Rare Earth Sample

作　　者：马嫱[1] 肖伟剑 陈勇飞[3] 林碧芬[3] 蔡继杰[3] 

机构地区：[1]厦门大学嘉庚学院环境科学与工程系,福建漳州363105 [2]厦门市环境监测中心站,福建厦门361012 [3]厦门出入境检验检疫局,福建厦门361026

出　　处：《稀土》2016年第1期110-115,共6页Chinese Rare Earths

基　　金：国家质检总局科技计划项目(2013IK020);福建省中青年教师教育科研项目(JA15619)

摘　　要：利用无源效率刻度方法进行建模、效率拟合及伽玛谱分析对稀土精矿、矿渣及最终产品高纯稀土样品的放射性做了调查,结果表明,稀土精矿、矿渣和高纯稀土中均含有放射性核素,但各样品中放射性核素的含量具有明显差异,且铀(钍)系母子体间放射性长期平衡已被破坏。各稀土样品中铀系核素的活度浓度变化范围为33.6 Bq/kg^18322.3 Bq/kg,钍系核素的活度浓度变化范围为4.1 Bq/kg^10442.8 Bq/kg。所有样品中均含有锕系放射性核素,基本处于放射性平衡状态,各样品中核素的活度浓度变化范围最大,为23.8 Bq/kg^25320.2 Bq/kg。对稀土冶炼过程各产品的放射性核素检测分析结果表明,有些生产工艺会去除大部分天然铀系、钍系放射性核素、227Ac以及少量的138La;也有些生产工艺对放射性影响很小;甚至在含量为99.99%的高纯氧化镧产品中依旧含有放射性227Ac和138La,准确地检测可以对生产过程起指导作用。In the process of radioactive detection of rare earth concentrates,residues and final product purity rare earth,HPGe γ spectrometry sourceless efficiency calibration was used in modeling and efficiency fitting. The results show that the rare earth concentrates,residues and high purity rare earth products all contain radionuclides,but the radioactive levels in each sample are significantly different. And the radioactive equilibrium of uranium（ thorium） series has been destroyed. In different rare earth samples,the radioactive level of uranium series＇ nuclide is between 33. 6Bq / kg ~ 18322. 3 Bq / kg and the thorium series＇ nuclide＇s radioactivity is between 4. 1Bq / kg ~ 10442. 8 Bq / kg. Actinium series＇ nuclide can be found in all samples and basically at the radioactive equilibrium state. It has a widest range of radioactive level,23. 8Bq / kg ~ 25320. 2Bq / kg. The results of radioactive nuclide analysis for the production and residues of the different process in rare earth smelting show that the most of natural uranium and thorium series nuclide,227 Ac and some138 La can be transferred to the residues. But on the other hand,the radioactive level of some residues is very low.227 Ac and138La was existed even in the content of 99. 99%purity lanthanum oxide. And the accurate detection can guide the process of production.

关 键 词：无源效率刻度 放射性平衡 稀土产品 γ能谱分析 

分 类 号：TL817[核科学技术—核技术及应用]