関連する実験動画
Updated: Jul 12, 2026

08:53
Automated 90Sr Separation and Preconcentration in a Lab-on-Valve System at Ppq Level
Published on: June 6, 2018
まとめ
ポロニウムハロの新たな分析により,これまで知られていなかった鉛同位体の比率と,新しい低エネルギーアルファエミッターの証拠が明らかになった. これらの発見は,放射性崩壊と核物理学の現在のモデルに挑戦しています.
科学分野:
- 地質化学 地質化学
- 核物理学 核物理学とは
- 放射性分解の研究 放射性分解の研究
背景:
- ポロニウムハロは,アルファ崩壊の微小な証拠である.
- これらのハロの鉛同位体の比率を理解することは,ウラン・ソリウム分解連鎖の洞察を提供します.
研究 の 目的:
- ポロニウムハロインクルージョンにおけるこれまで報告されていない鉛同位体の比率を調査する.
- ハロの特徴に基づいて,潜在的な新しいアルファエミッターを特定する.
主な方法:
- 精密な同位素比測定のためのイオンマイクロプローブ技術を活用しました.
- 分析されたポロニウムハロ構造は,矮星型と"X"ハロ型を含む.
主要な成果:
- 鉛206/鉛207の比率を20から60に決定し,放射性鉛がウラン崩壊によってサポートされていないことを示唆しています.
- トリウム分解によって支持されない放射性鉛-208の観測証拠.
- 未知の低エネルギーアルファエミッターを示す新しい矮星ハロサイズが特定されました.
- "X"ハロは,エネルギーが3〜7 MeVの間の未知のアルファエミッターのシリーズを示唆しています.
結論:
- 発見は,異常な鉛同位体と,以前未発見のアルファ放射性同位体の存在を示しています.
- これらの結果は,既知の放射性崩壊モデルと核プロセスの再評価を必要とします.
関連する概念動画
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...
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:
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.
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 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...
Nuclear Transmutation
Nuclear transmutation is the conversion of one nuclide into another. It can occur by the radioactive decay of a nucleus, or the reaction of a nucleus with another particle. The first manmade nucleus was produced in Ernest Rutherford’s laboratory in 1919 by a transmutation reaction, the bombardment of one type of nuclei with other nuclei or with neutrons. Rutherford bombarded nitrogen-14 atoms with high-speed α particles from a natural radioactive isotope of radium and observed protons being...

