核と核の衝突で予期せぬ融合の阻害
A C Berriman1, D J Hinde, M Dasgupta
1Department of Nuclear Physics, Research School of Physical Sciences and Engineering, Australian National University, Canberra, ACT, Australia.
Nature
|September 15, 2001
まとめ
研究者は重原子核の融合を調査し,予測よりも低い投射物標的の電荷産物でも抑制された融合と準分裂を観察しました. これらの発見は,現在の核融合モデルに異議を唱えている.
科学分野:
- 核物理学 核物理学とは
- 重イオン衝突による重イオン衝突
- 超重元素 超重元素について
背景:
- 不安定な超重原子核は,安定した原子核を融合させることで合成される.
- 質量移転後に原子核が分離するプロセスである準分裂は,核融合を大幅に阻害する.
- 準分裂を理解することは,新しい超重元素を合成するために不可欠です.
研究 の 目的:
- 重原子核における核融合の阻害と準核分裂の発生を調査する.
- 核融合阻害のためのZ1Z2電荷製品の値に関する理論的予測をテストする.
主な方法:
- 重原子核を含む3つの核融合反応を実施した.
- 研究された反応は,Z1Z2電荷産物で,理論的に予測された阻害値の約半分であった.
- 超重核216Ra.の形成を測定した.
主要な成果:
- 核融合阻害の明確な証拠が観察されました.
- 研究された反応における準分裂の存在を確認した.
- Z1Z2の値は,以前は阻害を引き起こすと考えられていたよりも著しく低い値で結果が得られました.
結論:
- 実験結果は,核融合と核分裂の標準モデルと矛盾しています.
- 準分裂は,予測されたより低いZ1Z2値で発生し,超重元素合成に影響を与えます.
- 観測された核融合阻害を説明するために,さらなる理論的発展が必要である.
関連する概念動画
Nuclear Stability
20.5K
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...
To hold positively...
20.5K
Nuclear Binding Energy
12.3K
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...
12.3K
Nuclear Fission
9.5K
Many heavier elements with smaller binding energies per nucleon can decompose into more stable elements that have intermediate mass numbers and larger binding energies per nucleon—that is, mass numbers and binding energies per nucleon that are closer to the “peak” of the binding energy graph near 56. Sometimes neutrons are also produced. This decomposition of a large nucleus into smaller pieces is called fission. The breaking is rather random with the formation of a large...
9.5K
Nuclear Fusion
33.3K
The process of converting very light nuclei into heavier nuclei is also accompanied by the conversion of mass into large amounts of energy, a process called fusion. The principal source of energy in the sun is a net fusion reaction in which four hydrogen nuclei fuse and ultimately produce one helium nucleus and two positrons.
A helium nucleus has a mass that is 0.7% less than that of four hydrogen nuclei; this lost mass is converted into energy during the fusion. This reaction produces about...
A helium nucleus has a mass that is 0.7% less than that of four hydrogen nuclei; this lost mass is converted into energy during the fusion. This reaction produces about...
33.3K
Nuclear Transmutation
13.0K
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...
13.0K
Mismatch Repair
5.4K
Organisms are capable of detecting and fixing nucleotide mismatches that occur during DNA replication. This sophisticated process requires identifying the new strand and replacing the erroneous bases with correct nucleotides. Mismatch repair is coordinated by many proteins in both prokaryotes and eukaryotes.
The Mutator Protein Family Plays a Key Role in DNA Mismatch Repair
The human genome has more than 3 billion base pairs of DNA per cell. Prior to cell division, that vast amount of genetic...
The Mutator Protein Family Plays a Key Role in DNA Mismatch Repair
The human genome has more than 3 billion base pairs of DNA per cell. Prior to cell division, that vast amount of genetic...
5.4K


