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Updated: Jan 19, 2026
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Mass Defect, Nuclear Binding Energy and Nuclear Stability
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229Th核時計の移行のエネルギー
Benedict Seiferle1, Lars von der Wense2, Pavlo V Bilous3
1Ludwig-Maximilians-University Munich, Garching, Germany. benedict.seiferle@physik.uni-muenchen.de.
Nature
|September 13, 2019
まとめ
研究者達は,核光学時計の開発に不可欠な,トリウム229の同位体状態のエネルギーを正確に測定しました. この突破は 超精度の計時と 物理学の新たな応用への道を開きます
科学分野:
- 核物理学
- 原子物理学
- メトロロジー
背景:
- トリウム-229 (229mTh) の最初の興奮異体状態は,その低い興奮エネルギーと長い放射線寿命のために,核光学時計の有望な候補である.
- 核時計の開発は,地質学と基本的恒定研究における応用が,229mThエネルギーに関する不正確な知識によって妨げられてきた.
- 原子時計は 核時計の限界を 克服しようとしています
研究 の 目的:
- 229mThの同位体状態から基本状態への移行エネルギーを高精度で直接測定する.
- この核移行に対応する波長をレーザースペクトロスコピーのアプリケーションで決定する.
- 精度計測を進めて 精度の高い核光学時計の開発を可能にします
主な方法:
- 中性229mTh原子の分解時に放出された内部変換電子のスペクトロスコーピー.
- 0.17電子ボルトの不確実性を持つ移行エネルギーの直接測定.
- 測定されたエネルギーを用いて移行波長を計算する.
主要な成果:
- 229mThの基本状態への移行エネルギーは,0.17 eVの標準偏差の不確実性で測定されました.
- エネルギーは149.7 ± 3.1ナノメートルの移行波長に対応します.
- この波長は,高ハーモニック生成を用いたレーザースペクトロスコーピーを介してアクセスできます.
結論:
- 229mThの移行エネルギーの正確な測定は,高解像度レーザースペクトロスコピーを円滑にします.
- この発見は前例のない精度を持つ 核光学時計の開発に向けた 重要な一歩です
- この研究は 精度計測を大幅に進めるために 核物理学と原子物理学を組み合わせています
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