Measurement of the half-life of ^79Se with accelerator mass spectrometry

• Published in: Chinese physics C 2014-10, Vol.38 (10), p.65-68
• Main Author: 窦亮 姜山 王晓波 董克君 武绍勇 杨旭冉 王小明 蓝小淅 夏清良 何明
• Format: Article
• Language: English
• Subjects: 79Se; AMS; AMS系统; attenuator; half-life; NUCLEAR PHYSICS AND RADIATION PHYSICS; 加速器质谱; 半衰期测量; 搜索引擎; 放射性核素; 测定; 液体闪烁; 短寿命核素
• ISSN: 1674-1137; 0254-3052
• DOI: 10.1088/1674-1137/38/10/106204

The accelerator mass spectrometry（AMS） is an effective method for the determination of the half-life of long-lived radionuclides. In this paper, we report a method for measurement of the half-life of ^79Se. The number of ^79Se atoms was determined from measured ^79Se/Se absolute ratios with the AMS system at the China Institute of Atomic Energy and the decay rate of ^79Se was determined by counting the emitted β-rays with a liquid scintillation spectrometer. The major improvements of our measurements include using the high abundance of an ^79Se sample which was cooled for many years to exclude the interference of short-lived nuclides, the extraction of SeO-2molecular ions, that results in a suppression of the ^79Br background by as much as about five orders of magnitude. Also, an AMS measurement of the absolute ratio of ^79Se/Se was developed to avoid systematic errors. The results show that ^79Se/Se is（2.35±0.12）×10^-7in the reference sample and the radioactivity of ^79Se is（1.24±0.05） Bq/g, so the half-life of ^79Se is（2.78±0.18）×10^5a.