Is There an Island of Stability in Nuclear Physics?

[qedprigmosyno]

Just for the record: http://newscenter.lbl.gov/press-releases/2009/09/24/114-confirmed/
Cal Pride!

Does anyone want to explain specifically how or why there is an island of stability?

 

[Astronuc]

Just for the record: http://newscenter.lbl.gov/press-releases/2009/09/24/114-confirmed/
Cal Pride!

Does anyone want to explain specifically how or why there is an island of stability?

Stability would be based on the right pairing or arrangement among the population of neutrons and protons.

Beginning in the late 1950s, scientists including Gertrude Scharff-Goldhaber at Brookhaven and theorist Wladyslaw Swiatecki, who had recently moved to Berkeley and is a retired member of Berkeley Lab’s NSD, calculated that superheavy elements with certain combinations of protons and neutrons arranged in shells in the nucleus would be relatively stable, eventually reaching an “Island of Stability” where their lifetimes could be measured in minutes or days – or even, some optimists think, in millions of years. Early models suggested that an element with 114 protons and 184 neutrons might be such a stable element. Longtime Berkeley Lab nuclear chemist Glenn Seaborg, then Chairman of the Atomic Energy Commission, encouraged searches for superheavy elements with the necessary “magic numbers” of nucleons.
. . . .
.Says Gregorich, “Based on the ideas of the 1960s, we thought when we got to element 114 we would have reached the Island of Stability. More recent theories suggest enhanced stability at other proton numbers, perhaps 120, perhaps 126. The work we’re doing now will help us decide which theories are correct and how we should modify our models.”

Nitsche adds, “During the last 20 years, many relatively stable isotopes have been discovered that lie between the known heavy element isotopes and the Island of Stability – essentially they can be considered as ‘stepping stones’ to this island. The question is, how far does the Island extend – from 114 to perhaps 120 or 126? And how high does it rise out the Sea of Instability.”
. . . .

http://www.sjsu.edu/faculty/watkins/magicnumber.htm

Maria Goeppert-Mayer and other physicists examining the properties of the isotopes of elements discerned that isotopes in which the proton and/or the neutron numbers were particular values have notable properties such as stability.

http://physicsworld.com/cws/article/news/22492

 

[lakshwadeep]

Here's a cool clip from NOVA about the island of stability:
http://www.pbs.org/wgbh/nova/sciencenow/3313/02.html

 

[Astronuc]

Nuclear missing link created at last: Superheavy element 117 (Update)

The lifetime of element 117 bolsters confidence in theories that predict that superheavy elements occupy an "island of stability" in a chart of elements and their isotopes. The island is indicated by the red region at the upper right. Atoms in the stable region decay much more slowly than atoms with characteristics that place them nearby, but outside, the region.

Credit: American Physical Society

http://phys.org/news189797683.html (April 06, 2010)

The two-year experimental campaign began at the High Flux Isotope Reactor in Oak Ridge with a 250-day irradiation to produce 22 mg of berkelium. This was followed by 90 days of processing at Oak Ridge to separate and purify the berkelium, target preparation at Dimitrovgrad, 150 days of bombardment at one of the world's most powerful heavy ion accelerators at Dubna, data analysis at Livermore and Dubna, and assessment and review of the results by the team. The entire process was driven by the 320-day half-life of the berkelium target material.
. . . .
Element 117 was the only missing element in row seven of the periodic table. On course to the island of stability, researchers initially skipped element 117 due to the difficulty in obtaining the berkelium target material. The observed decay patterns in the new isotopes from this experiment, as close as researchers have ever approached the island of stability, continue a general trend of increasing stability for superheavy elements with increasing numbers of neutrons in the nucleus. This provides strong evidence for the existence of the island of stability.
. . . .

http://www.webelements.com/ununseptium/

http://www.ornl.gov/info/ornlreview/v43_2_10/article02.shtml

Presentation on Element 117 - http://neutrons.ornl.gov/conf/TRTR_IGORR/TechnicalSessions/1_Welcoming%20Session/Roberto_Presentation_TRTR%20IGORR_10.pdf (11.8 MB)

 

[Acut]

Stability would be based on the right pairing or arrangement among the population of neutrons and protons.


http://www.sjsu.edu/faculty/watkins/magicnumber.htm

How do protons and neutrons organize themselves in the nucleus? Is there an analogy between this and the best known example of electrons organized in shells in the electrons or is it an unrelated phenomenon?