関連する実験動画
Updated: Jul 12, 2026

10:42
Preparing an Isotopically Pure 229Th Ion Beam for Studies of 229mTh
Published on: May 3, 2019
ベリリウム-7の放射性崩壊定数の圧力依存度
まとめ
研究者は,ダイヤモンドアンビルプレスを用いてベリリウム-7酸化物を圧縮し,その腐敗定数を測定しました. 高圧はベリリウム-7からリチウム-7への電子捕獲分解率をわずかに増加させることが判明しました.
科学分野:
- 核物理学 核物理学とは
- 物質科学は,極端な条件下での科学です.
背景:
- 放射性同位体の分解速度は,外部の物理条件によって影響を受けます.
- 電子捕獲分解は,核物理学の重要なプロセスであり,特に軽い元素には重要です.
研究 の 目的:
- ベリリウム-7 (7Be) の電子捕獲分解定数に対する高圧の影響を調査する.
- 7Beの腐敗の圧力依存度を,新しいダイヤモンドアンビルプレス設計を用いて定量化する.
主な方法:
- 新たに設計されたダイヤモンド・アンビル・プレスを使って,7Be オキシードサンプルを120キロバー,210キロバー,270キロバーの圧力にさらした.
- 7Beの圧縮されたサンプルと非圧縮されたサンプルの両方の衰退定数 (λ) を測定しました.
- 圧力係数を決定するために,実験データに最小二乗のフィットを適用した.
主要な成果:
- 7Beの崩壊定数は,加圧によって増加することが観察されました.
- 圧力係数 (Kp) の定量値は (2.2 ± 0.1) x 10−5 kbar−1.1) と決定されました.
- これは,圧力の電子捕獲プロセスへの影響が測定可能だが,小さいことを示している.
結論:
- 高圧は,電子捕獲の衰退率7Be.に実証的に影響を及ぼします.
- この発見は,軽い元素の核崩壊過程の圧力誘発による変化の実験的証拠を提供する.
- この研究は,極端な条件下での基本的な核物理学の理解に貢献しています.
さらに関連する動画
08:42High-Sensitivity Nuclear Magnetic Resonance at Giga-Pascal Pressures: A New Tool for Probing Electronic and Chemical Properties of Condensed Matter under Extreme Conditions
Published on: October 10, 2014
08:43Separation of Uranium and Thorium for 230Th-U Dating of Submarine Hydrothermal Sulfides
Published on: May 20, 2019
関連する概念動画
Radioactive Decay and Radiometric Dating
Radioactivity is a spontaneous disintegration of an unstable nuclide and is a random process, as all the nuclei in the sample do not decay simultaneously. The number of disintegrations per unit time is called the activity (A), which is directly proportional to the number of nuclei in the sample. The decay constant (λ) is an average probability of decay per nucleus in unit time.
Nuclear Stability
Protons and neutrons, collectively called nucleons, are packed together tightly in a nucleus. With a radius of about 10−15 meters, a nucleus is quite small compared to the radius of the entire atom, which is about 10−10 meters. Nuclei are extremely dense compared to bulk matter, averaging 1.8 × 1014 grams per cubic centimeter. If the earth’s density were equal to the average nuclear density, the earth’s radius would be only about 200 meters.
To hold positively charged protons together in the...
To hold positively charged protons together in the...
Types of Radioactivity
The most common types of radioactivity are α decay, β decay, γ decay, neutron emission, and electron capture.
Alpha (α) decay is the emission of an α particle from the nucleus. For example, polonium-210 undergoes α decay:
Alpha (α) decay is the emission of an α particle from the nucleus. For example, polonium-210 undergoes α decay:
Radioactivity and Nuclear Equations
Nuclear chemistry is the study of reactions that involve changes in nuclear structure. The nucleus of an atom is composed of protons and, except for hydrogen, neutrons. The number of protons in the nucleus is called the atomic number (Z) of the element, and the sum of the number of protons and the number of neutrons is the mass number (A). Atoms with the same atomic number but different mass numbers are isotopes of the same element.
A nuclide of an element has a specific number of protons and...
A nuclide of an element has a specific number of protons and...
Nuclear Binding Energy
The difference between the calculated and experimentally measured masses is known as the mass defect of the atom. In the case of helium-4, the mass defect indicates a “loss” in mass of 4.0331 amu – 4.0026 amu = 0.0305 amu. The loss in mass accompanying the formation of an atom from protons, neutrons, and electrons is due to the conversion of that mass into energy that is evolved as the atom forms. The nuclear binding energy is the energy produced when the atoms’ nucleons are bound together;...
Consecutive Reactions
Consecutive reactions involve a sequence where the product of a preceding reaction becomes the reactant for the subsequent one. In a simple scheme, A transforms into B, which further reacts to form C, with rate constants k1 and k2, respectively. This concept is evident in the radioactive decay series. Assuming an initial state with only A present, the conservation of matter leads to three coupled differential equations, determining the concentrations of A, B, and C over time.The rate of change...