To probe the evolution of atomic nuclei with different shape —a factor which affects atomic stability—a large team of international researchers has added neutrons to zirconium atoms and revealed the possibility of very unusual shapes. “The shape of a nucleus reflects the symmetry of its quantum state,” explains team member Hiroyoshi Sakurai from the RIKEN Nishina Center for Accelerator-Based Science in Wako. This result helps us to understand how many neutrons are needed for the most stable nuclei.
Most atoms can exist in one of several alternative forms called isotopes, depending on the number of neutrons in their core. Naturally occurring, stable, atoms tend to have between 1 and 1.5 neutrons per proton. However, synthetically generated atoms with higher neutron–proton ratios can reveal much about changes within an atomic nucleus.
The protons and neutrons in a nucleus usually form arrangements of concentric spherical shells. In some cases, however, the outermost particles exist further from the center than normal. This can lead to nuclei that are wider than they are long. Just as atoms with a specific number of protons can exist as different isotopes, atoms with a specific number of protons and neutrons can exist as different nuclear isomers—nuclei with different shapes. “By measuring the shape of nuclei, we are probing the internal symmetry in the nucleus—the so-called shell structure,” explains Sakurai.
At the Radioactive Isotope Beam Factory in Japan, operated jointly by RIKEN and The University of Tokyo, the researchers experimented with zirconium atoms that have 40 protons and, in their stable form, between 50 and 52 neutrons. They created zirconium atoms with as many as 68 neutrons through collisions between uranium and beryllium atoms. After filtering isotopes from the remnants of the collision, they measured the rate of decay of beta and gamma radiation emitted by the quickly decaying, unstable synthetic atoms. The measurements showed that these nuclei changed shape from spherical to oblate.
The degree of deformation of the zirconium nuclei increased as Sakurai and colleagues added more neutrons, but this trend stopped when they reached 64 neutrons. This result raises the intriguing prospect of a tetrahedral-shaped isomer of zirconium-108—an isotope with 68 neutrons—which has been predicted previously by other researchers. However, further work is needed to verify this.
“We next hope to gain further insight into the evolution of nuclear isomers by extending our study to strontium atoms,” Sakurai says.
The corresponding author for this highlight is based at the Radioactive Isotope Physics Laboratory, RIKEN Nishina Center for Accelerator-Based ScienceReference:
Significantly more productivity in USP lasers
06.12.2016 | Fraunhofer-Institut für Lasertechnik ILT
Shape matters when light meets atom
05.12.2016 | Centre for Quantum Technologies at the National University of Singapore
In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.
Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
07.12.2016 | Health and Medicine
07.12.2016 | Life Sciences
07.12.2016 | Health and Medicine