相关实验视频
Updated: May 23, 2026

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Preparing an Isotopically Pure 229Th Ion Beam for Studies of 229mTh
Published on: May 3, 2019
收回:测量了更短的146Sm半衰期,并对太阳系中146Sm-142Nd时间表的影响
N Kinoshita1, M Paul, Y Kashiv
1Research Facility Center for Science and Technology, University of Tsukuba, Tsukuba, Japan.
概括
萨马-146 (146Sm) 的半衰期,这是确定太阳系早期事件日期的关键同位素,已修订为6800万年. 这一发现表明,行星分化的时间表更早,更短.
科学领域:
- * 核天体物理学和地球化学.
- * 放射测年法和宇宙化学.
- * 同位素地质学和行星科学.
背景情况:
- *已灭绝的放射性核酸萨马-146 (146Sm) 对于通过其子产物-142 (142Nd) 来测定早期太阳系材料的年代是至关重要的.
- *准确的半衰期和146Sm的初始丰度对于精确的时间解释至关重要.
- *以前对146Sm半衰期和初始丰度的估计导致了早期太阳系时间表的不确定性.
研究的目的:
- * 通过测量α活性和原子比,精制-146 (146Sm) 的半衰期.
- *重新计算太阳系早期146Sm的初始丰度.
- * 用修订的146Sm数据重新评估行星地幔分化事件的时间.
主要方法:
- *对-146 (146Sm) 与-147 (147Sm) 的α活性比率进行分析.
- * 确定-146 (146Sm) 与-144 (144Sm) 的原子比.
- * 146Sm142Nd同位素系统的应用,以测定地球,月球和火星样品的日期.
主要成果:
- * -146 (146Sm) 的半衰期被确定为68±700万年,比以前公认的值要短得多.
- * 早期太阳系中146Sm的初始丰度 (146Sm/144Sm) ((0)) 估计为0.0094 ± 0.0005.5.
- *使用146Sm142Nd的行星化地幔分化事件的约会表明更早和更短的时间跨度.
结论:
- * 修订后的半衰期和萨马-146 (146Sm) 的初始丰度需要对早期太阳系时间表进行调整.
- *行星分化过程发生在压缩的时间尺度上,并且比以前认为的更早.
- * 这项研究提供了一个更准确的同位素计时计,以了解陆地行星和太阳系的初始演变.
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