Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

FSU physicist takes a trip to nuclear 'island of inversion'

13.08.2007
Far from the everyday world occupied by such common elements such as gold and lead lies a little-understood realm inhabited by radioactive, or unstable, elements.

Recently, a nuclear physicist from Florida State University collaborated with other scientists from the United States, Japan and England in an experiment that illustrated how the “normal” rules of physics don’t apply for some of these radioactive elements.

Kirby W. Kemper, the Robert O. Lawton Distinguished Professor of Physics and vice president for Research at FSU, took part in an experiment at the National Superconducting Cyclotron Laboratory, a national user facility located at Michigan State University in East Lansing, Mich. In the experiment, Kemper and his colleagues found that the structure of atomic nuclei of one radioactive isotope in particular -- magnesium-36, or Mg-36 -- is odd and unexpected.

“Ten years ago, complicated experiments like this one were a dream,” Kemper said. “Five years ago, we thought that in the next 10 years we would be able to carry it out. Now we have done one and so are much further along in experimental capability than even our wildest hopes.”

Protons and neutrons that comprise a nucleus array themselves in shells, each shell with a different energy level, Kemper explained. The phenomenon is described by the nuclear shell model. According to the model, specific numbers of protons and neutrons lead to shell structures that are especially stable -- except, that is, for nuclei of elements in the so-called “island of inversion.” There, ground-state nuclei that otherwise would have fairly typical shell structures adopt weird and strongly deformed structures. Mapping out which nuclei are within or outside the island of inversion helps researchers extend the usefulness of the nuclear shell model, which earned its creators the Nobel Prize for Physics in 1963 and continues to be a powerful tool for understanding the structure of nuclei.

Kemper collaborated with researchers from Michigan State University, the University of Tokyo and RIKEN in Japan, and the University of Surrey in England to study Mg-36. Contemporary theoretical models suggested that its nucleus, with 12 protons and 24 neutrons, should exist just within the island of inversion. But until the team’s result, which will appear in Physical Review Letters, experimentalists hadn’t made the necessary measurements of the rare magnesium isotope to know for sure.

The experiment was conducted at the National Superconducting Cyclotron Laboratory’s Coupled Cyclotron Facility, where a beam of calcium-48 nuclei was generated and directed at a beryllium target. This generated a variety of reaction products, including silicon-38, or Si-38. A large scientific instrument known as a fragment separator then was tuned to allow Si-38 to pass through and continue down the beam line.

Downstream, these Si-38 isotopes struck a second beryllium target, resulting in the creation of a smattering of new nuclei, including Mg-36. The beam was turned up into the focal plane of a three-story-tall spectrograph -- a giant analytical tool -- that was set to accept only Mg-36. When analyzed, the spectroscopic data indicated that Mg-36 is in fact within the island of inversion.

“Gamma-ray spectroscopy for Mg-36 has never been done because this nucleus is incredibly hard to reach,” said Alexandra Gade, an assistant professor at the National Superconducting Cyclotron Laboratory and lead author of the Physical Review Letters paper. “It’s not just another nucleus.”

For every 400,000 Si-38 nuclei impacting the second target, just one Mg-36 nucleus was produced.

“To the average person, this might seem like a lot of work for not a whole lot of benefit,” Kemper said. “But experiments like this are really all about broadening our understanding of matter -- how it is formed, how it behaves under extreme conditions, and what universal rules apply to it. This is fundamental to increasing our understanding of all matter in the universe. After all, even common elements such as gold and lead had to come from somewhere.”

Kirby Kemper | EurekAlert!
Further information:
http://www.fsu.edu

More articles from Physics and Astronomy:

nachricht Engineering team images tiny quasicrystals as they form
18.08.2017 | Cornell University

nachricht Astrophysicists explain the mysterious behavior of cosmic rays
18.08.2017 | Moscow Institute of Physics and Technology

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

A Map of the Cell’s Power Station

18.08.2017 | Life Sciences

Engineering team images tiny quasicrystals as they form

18.08.2017 | Physics and Astronomy

Researchers printed graphene-like materials with inkjet

18.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>