関連する実験動画
Updated: Jul 12, 2026

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Hyperpolarized Xenon for NMR and MRI Applications
Published on: September 6, 2012
まとめ
井戸ガスの分析により,過剰なクセノン-129が検出され,これは地球が早期に脱ガスしたことを示している. この発見は,地球と隕石の年齢の違いを制限するのに役立ちます.
科学分野:
- 地質化学 地質化学
- 宇宙化学 (コスモケミストリー)
- 同位体地質学とは,同位体地質学である.
背景:
- 地上および地外のサンプルのキセノン同位体は,惑星の形成と進化の洞察を提供します.
- 絶滅したヨウ素-129 (129I) がクセノン-129 (129Xe) に崩壊することは,初期の太陽系イベントの重要なクロノメーターです.
研究 の 目的:
- 二酸化炭素が豊富な井戸ガスにおけるクセノンの同位体組成を調べるため.
- クセノン同位体異常を用いて,地球の形成と大気進化のタイミングを,隕石と比較して制限する.
主な方法:
- 井戸からのガスサンプルにおけるクセノン同位体の分析.
- 放射性クセノン-129 (129Xe) と分裂生成クセノン同位体の測定.
主要な成果:
- 放射性クセノン-129 (129Xe) の有意な過剰が検出され,絶滅したヨウ素-129 (129I) の腐敗に起因した.
- 重いクセノンイソトープのより小さな過剰は,分裂産物として特定されました.
- 同位体データは,地球と最も古い隕石の年齢の違いに厳しい制約を課しています.
結論:
- 井戸ガスに過剰な放射性クセノン-129 (129Xe) の存在は,地球の材料の限られた,初期段階の脱ガス化を示唆しています.
- この観測は,非常に初期の,定量的な脱ガス現象,または地球の形成以来,継続的な,不完全な脱ガス現象のいずれかを支持しています.
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.
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:
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...
Noble Gases
The elements in group 18 are noble gases (helium, neon, argon, krypton, xenon, and radon). They earned the name “noble” because they were assumed to be nonreactive since they have filled valence shells. In 1962, Dr. Neil Bartlett at the University of British Columbia proved this assumption to be false.
Isotopes and Radioisotopes
In the early 1900s, English chemist Frederick Soddy realized that an element could have atoms with different masses that were chemically indistinguishable. These different types are called isotopes — atoms of the same element that differ in mass. Isotopes differ in mass because they have different numbers of neutrons but are chemically identical because they have the same number of protons. Soddy was awarded the Nobel Prize in Chemistry in 1921 for this discovery.
An isotope containing more...
An isotope containing more...
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...

