* Astronomy

Blobrana · L

RE: Tin

Blobrana · L

Doubly Magic nuclear physics answers fundamental questions about the universe

Research into the structure of extremely rare atomic nuclei, and how they decay, is providing the deepest insights yet into the formation of heavy elements that occur during explosions on the surface of stars. The research carried out by an international team of scientists at the GSI Helmholtz Centre for Heavy Ion Research in Darmstadt, Germany, represents a major milestone in current nuclear structure physics research, the results of which have been published in Nature, 20th June 2012.
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Blobrana · L

Tin-100, a doubly magic nucleus

A few minutes after the Big Bang the universe contained no other elements than hydrogen and helium. Physicists of the Technische Universitaet Muenchen (TUM), the Cluster of Excellence "Universe" and the Helmholtz Centre for Heavy Ion Research (GSI) have now succeeded in producing tin-100, a very instable yet important element for understanding the formation of heavier elements. The researchers report on their results in the current edition of the scientific journal Nature.
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Blobrana · L

Zinn-100, ein doppelt magischer Kern

Wenige Minuten nach dem Urknall gab es im Universum nur die Elemente Wasserstoff und Helium. Alle anderen chemischen Elemente entstanden erst sehr viel später. Physikern der Technischen Universität München (TUM), des Exzellenzclusters Universe und des Helmholtz-Instituts für Schwerionenforschung (GSI) ist es nun gelungen, Zinn-100 herzustellen, ein zwar sehr instabiles, aber für das Verständnis der Bildung schwererer Elemente sehr wichtiges Element. Uber ihre Ergebnisse berichten sie in der aktuellen Ausgabe des Wissenschaftsjournals Nature.
Stabiles Zinn, so wie wir es kennen, besitzt 112 Kernteilchen, 50 Protonen und 62 Neutronen. Die Neutronen wirken dabei gewissermaben wie ein Puffer zwischen den sich elektrisch abstobenden Protonen und verhindern, dass normales Zinn zerfällt. Nach dem Schalenmodell der Kernphysik ist die 50 eine "magische Zahl", bei der besondere Eigenschaften auftreten. Zinn-100 ist mit 50 Protonen und 50 Neutronen "doppelt magisch" und daher für die Kernphysik besonders interessant.
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Blobrana · L

The 'Magic' of Tin

In the journal Nature, Rutgers physicists recently reported studies on tin that add knowledge to a concept known as magic numbers while perhaps helping scientists to explain how heavy elements are made in exploding stars.
Physicists who study the nuclei of atoms - the dense cluster of protons and neutrons at the atom's center - apply the "magic" moniker to elements with a certain number of protons or combination of protons and neutrons. At these numbers - 2, 8, 20, 28, 50, 82, and 126 - the protons and neutrons are tightly bound together, giving many "magic" elements a high degree of stability in their nuclei.
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Blobrana · L

Title: The magic nature of 132Sn explored through the single-particle states of 133Sn
Authors: K. L. Jones, A. S. Adekola, D. W. Bardayan, J. C. Blackmon, K. Y. Chae, K. A. Chipps, J. A. Cizewski, L. Erikson, C. Harlin, R. Hatarik, R. Kapler, R. L. Kozub, J. F. Liang, R. Livesay, Z. Ma, B. H. Moazen, C. D. Nesaraja, F. M. Nunes, S. D. Pain, N. P. Patterson, D. Shapira, J. F. Shriner Jr, M. S. Smith, T. P. Swan & J. S. Thomas

Atomic nuclei have a shell structure in which nuclei with 'magic numbers' of neutrons and protons are analogous to the noble gases in atomic physics. Only ten nuclei with the standard magic numbers of both neutrons and protons have so far been observed. The nuclear shell model is founded on the precept that neutrons and protons can move as independent particles in orbitals with discrete quantum numbers, subject to a mean field generated by all the other nucleons. Knowledge of the properties of single-particle states outside nuclear shell closures in exotic nuclei is important for a fundamental understanding of nuclear structure and nucleosynthesis (for example the r-process, which is responsible for the production of about half of the heavy elements). However, as a result of their short lifetimes, there is a paucity of knowledge about the nature of single-particle states outside exotic doubly magic nuclei. Here we measure the single-particle character of the levels in 133Sn that lie outside the double shell closure present at the short-lived nucleus 132Sn. We use an inverse kinematics technique that involves the transfer of a single nucleon to the nucleus. The purity of the measured single-particle states clearly illustrates the magic nature of 132Sn.

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