克量粉末样品中低比活度放射性核素的γ能谱分析  

Analysis for low specific radioactive samples of gram level powder by γ spectrometer

作　　者：张佳媚[1] 倪建忠[1] 何小兵[1] 凡金龙[1] 

机构地区：[1]西北核技术研究所,西安710024

出　　处：《核技术》2010年第5期380-384,共5页Nuclear Techniques

摘　　要：报道了缺少小直径圆盘状体标准源条件下,快速简便地测定固体粉末样品中多种人工放射性核素比活度的γ能谱分析方法。取1g左右样品,装在特制的塑料盒中,形成Φ26mm×3mm的小圆盘状。由于样品的比活度较低,采用低源距(1cm,记为H1)测量。由于没有与样品圆盒相同形式的体标准源,利用直径26mm的60Co平面标准源在高源距(25cm,记为H25)测定若干放射性核素平面源的活度及峰效率,再测定H1的平面源峰效率。然后源距在H1基础上逐次增加1mm以测量平面源的峰效率,拟合峰效率随距离变化的函数,模拟得到厚度为3mm圆盘体标准源的峰效率。最终测定了样品比活度(包含自吸收校正)。与样品中两种核素的放化分析结果比对,测定结果偏差≤4%。In order to determine quickly and conveniently several man-made radionuclides of low-level specific radioactivity in batch of powder samples,the γ spectrometry non-destructive analysis is adopted.Each sample about 1 g in weight was loaded into a custom-made plastic box,forming a small disk of Φ26 mm×3 mm.Sample boxes were measured in the lower position,about 1 cm from the HPGe detector(referred as Position H1).Without the same solid standard source for efficiency calibration,so some planar sources(in same d...

关 键 词：放射性核素 γ能谱分析 γ射线全吸收峰探测效率 

分 类 号：R144[医药卫生—公共卫生与预防医学]