Related Experiment Video
Updated: Jul 4, 2026
08:55
Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses
Published on: June 7, 2018
Disentangling effects of nuclear structure in heavy element formation
D J Hinde1, R G Thomas, R du Rietz
1Department of Nuclear Physics, Research School of Physical Sciences and Engineering, The Australian National University, Canberra, ACT 0200, Australia.
Physical Review Letters
|June 4, 2008
Summary
Nuclear structure effects in quasifission were studied by forming the same compound nucleus using different isotopes. Nucleus alignment significantly broadens mass distributions at lower energies, challenging nuclear models.
Area of Science:
- Nuclear Physics
- Heavy-ion collisions
- Nuclear structure
Background:
- Disentangling nuclear structure effects in the entrance channel and dinuclear system is crucial for understanding heavy-ion reactions.
- Investigating quasifission dynamics requires detailed analysis of fragment properties.
Purpose of the Study:
- To investigate the influence of nuclear structure, specifically static deformation and nucleus alignment, on quasifission.
- To understand the energy dependence of mass distribution broadening in quasifission.
Main Methods:
- Formation of the compound nucleus 232Cm using different isotopes of Titanium (Ti) and Tungsten (W).
- Measurements conducted across a range of capture barrier energies.
- Analysis of mass-angle correlations of quasifission fragments.
Main Results:
- Alignment of the prolate deformed heavy nucleus is identified as the primary cause for the broadening of the quasifission fragment mass distribution at reduced beam energies.
- Complex, evolving mass-angle correlations provide more detailed information than integrated distributions.
Conclusions:
- Nuclear structure, particularly nucleus alignment, plays a dominant role in quasifission fragment mass distribution broadening.
- Observed mass-angle correlations offer stringent tests for theoretical models of quasifission.
Related Concept Videos
03:18Nuclear 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...
02:45Nuclear Fusion
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...
03:20Nuclear 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...
02:13Nuclear 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;...
01:06Nuclear Overhauser Enhancement (NOE)
Irradiation of a spin-active nucleus causes an increase or decrease in the signal intensity of neighboring nuclei that are not necessarily chemically bonded or involved in J-coupling. This phenomenon, called the nuclear Overhauser enhancement (NOE), results from through-space interactions between the nuclear spins. The NOE effect decreases with increasing internuclear distance and is generally not observed beyond 4 angstroms. In NOE, dipole-dipole interactions between neighboring spin-active...
03:08Atomic Radii and Effective Nuclear Charge
The elements in groups of the periodic table exhibit similar chemical behavior. This similarity occurs because the members of a group have the same number and distribution of electrons in their valence shells.