Determination of the half-life of 161 Tb

• Published in: Applied radiation and isotopes Vol. 193; p. 110647
• Main Authors: Dong, Jiangpeng, Bai, Tao, Hu, Yaowen, Zhang, Xiangbo, Fan, Jinlong, Dai, Yihua, Miao, Liangliang, Yu, Xiaoren, Li, Zhiming
• Format: Journal Article
• Language: English
• Published: England 01.03.2023
• Subjects: Half-life; Tb; Gamma ray spectrometry; Uncertainty budget

Tb has potential applications in targeted radionuclide therapy and nuclear forensic science. However, the half-lives of Tb in previous studies show a discrepancy. In this study, Tb samples were produced by irradiating Gd O with thermal neutron flux. A series of procedures were applied to extract a pure Tb solution and three solid samples were prepared. The half-life of Tb has been measured with a high-purity germanium (HPGe) detector. The time-dependency of the Tb activity was followed by assessing the count rate of their characteristic gamma-ray emissions at 48.9 keV and 74.6 keV over a period of 33-43 days. The experiment and uncertainty budget are discussed in detail. Different uncertainty propagation equations were applied for random uncertainties, medium-frequency deviations and potential systematic errors. The result for the Tb half-life of 6.967 (11) d was determined by the weighted mean of half-lives from three samples, which confirms that the half-life is longer than the of the current evaluated half-life of 6.89 (2) d. From all available quoted experimental values, a recommended half-life of 6.934 (14) d was determined by the power-moderated method (PMM). Based on recent four published half-life values, a half-life of Tb of 6.9582 (33) d was determined by the PMM analysis.