Featured Research

from universities, journals, and other organizations

Stabilizing shell effects in heaviest elements directly measured

Date:
August 10, 2012
Source:
Helmholtz Association of German Research Centres
Summary:
An international research team has succeeded in directly measuring the strength of shell effects in very heavy elements. The results provide information on the nuclear structure of superheavy elements, thus promising to enable drastically improved predictions concerning the location and extension of the island of stability of superheavy elements.

Enrique Minaya Ramirez and Michael Block at the SHIPTRAP setup at GSI.
Credit: G. Otto, GSI

An international research team has succeeded in directly measuring the strength of shell effects in very heavy elements. The results provide information on the nuclear structure of superheavy elements, thus promising to enable drastically improved predictions concerning the location and extension of the island of stability of superheavy elements. Indeed, it is expected that such elements with "magic" numbers of protons and neutrons will profit from enhanced stability due to shell effects, which endow them with long lifetimes. For the present measurements, performed on several isotopes of the elements nobelium and lawrencium, the scientists utilized the Penning trap facility SHIPTRAP at the GSI Helmholtz Centre for Heavy Ion Research in Darmstadt.

The results have been published in the journal Science.

So‐called "superheavy" elements owe their very existence exclusively to shell effects within the atomic nucleus. Without this stabilization they would disintegrate in a split second due to the strong repulsion between their many protons. The constituents of an atomic nucleus, the protons and neutrons, organize themselves in shells. Certain "magic" configurations with completely filled shells render the protons and neutrons to be more strongly bound together.

Long‐standing theoretical predictions suggest that also in superheavy elements, filled proton and neutron shells will give rise to extraordinarily stable and hence long‐lived nuclei: the "Island of stability." Still, after decades of research, its exact location on the chart of nuclei is a topic of intense discussions and no consensus has yet been reached. While some theoretical models predict a magic proton number to be at element 114, others prefer element 120 or even 126. Another burning question is whether nuclei situated on the island will live "only" hundreds or maybe thousands or even millions of years. Anyway, all presently known superheavy elements are short‐lived and none have been found in nature yet.

Precise information on the strength of shell effects that enhance binding energies of protons and neutrons for filled shells is a key ingredient for more accurate theoretical predictions. As the binding energy is directly related to the mass via Einstein's famous equation E=mc2, the weighing of nuclei provides access to the nuclear binding energies and thus the strength of the shell effects. With the ion‐trap facility SHIPTRAP, presently the most precise balance for weighing the heaviest elements, a series of very heavy atomic nuclei in the region of the magic neutron number N=152 have now been weighed with utmost precision for the first time. The studies at hand focused on nobelium (element 102) and lawrencium (element 103). These elements do not exist in nature, so the scientists produced them at the GSI's particle accelerator facility and captured them in the SHIPTRAP. The measurements had to be performed with just a handful of atoms: for the isotope lawrencium‐256 just about 50 could be studied during a measurement time of about 93 hours.

The new data will benchmark the best present models for the heaviest atomic nuclei and provide an important stepping stone to further refining the models. This will lead to more precise predictions on the location and extension of the "Island of stability" of superheavy elements.

The experiments were carried out by an international team led by scientists of GSI and the Helmholtz‐Institute Mainz (HIM) in collaboration with scientists from the universities of Giessen, Granada (Spain), Greifswald, Heidelberg, Mainz, Munich und Padua (Italy), as well as the Max‐Planck‐ Institute for Nuclear Physics Heidelberg and the PNPI St. Petersburg (Russia).


Story Source:

The above story is based on materials provided by Helmholtz Association of German Research Centres. Note: Materials may be edited for content and length.


Journal Reference:

  1. E. M. Ramirez, D. Ackermann, K. Blaum, M. Block, C. Droese, C. E. Dullmann, M. Dworschak, M. Eibach, S. Eliseev, E. Haettner, F. Herfurth, F. P. Hessberger, S. Hofmann, J. Ketelaer, G. Marx, M. Mazzocco, D. Nesterenko, Y. N. Novikov, W. R. Plass, D. Rodriguez, C. Scheidenberger, L. Schweikhard, P. G. Thirolf, C. Weber. Direct Mapping of Nuclear Shell Effects in the Heaviest Elements. Science, 2012; DOI: 10.1126/science.1225636

Cite This Page:

Helmholtz Association of German Research Centres. "Stabilizing shell effects in heaviest elements directly measured." ScienceDaily. ScienceDaily, 10 August 2012. <www.sciencedaily.com/releases/2012/08/120810133153.htm>.
Helmholtz Association of German Research Centres. (2012, August 10). Stabilizing shell effects in heaviest elements directly measured. ScienceDaily. Retrieved September 19, 2014 from www.sciencedaily.com/releases/2012/08/120810133153.htm
Helmholtz Association of German Research Centres. "Stabilizing shell effects in heaviest elements directly measured." ScienceDaily. www.sciencedaily.com/releases/2012/08/120810133153.htm (accessed September 19, 2014).

Share This



More Matter & Energy News

Friday, September 19, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Virtual Reality Headsets Unveiled at Tokyo Game Show

Virtual Reality Headsets Unveiled at Tokyo Game Show

AFP (Sep. 18, 2014) Several companies unveiled virtual reality headsets at the Tokyo Game Show, Asia's largest digital entertainment exhibition. Duration: 00:48 Video provided by AFP
Powered by NewsLook.com
Apple's iOS8 Includes New 'Killswitch' To Curb Theft

Apple's iOS8 Includes New 'Killswitch' To Curb Theft

Newsy (Sep. 18, 2014) Apple's new operating system, iOS 8, comes with Apple's killswitch feature already activated, unlike all the models before it. Video provided by Newsy
Powered by NewsLook.com
Stocks Hit All-Time High as Fed Holds Steady

Stocks Hit All-Time High as Fed Holds Steady

AP (Sep. 17, 2014) The Federal Reserve signaled Wednesday that it plans to keep a key interest rate at a record low because a broad range of U.S. economic measures remain subpar. Stocks hit an all-time high on the news. (Sept. 17) Video provided by AP
Powered by NewsLook.com
Space Race Pits Bezos Vs Musk

Space Race Pits Bezos Vs Musk

Reuters - Business Video Online (Sep. 16, 2014) Amazon CEO Jeff Bezos' startup will team up with Boeing and Lockheed to develop rocket engines as Elon Musk races to have his rockets certified. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins