|San José State University|
& Tornado Alley
Alpha Module Structure of Nuclei
The British science journal Nature in its online version of August 24, 2010 reported the following:
In 2002, Oak Ridge physicist Paul Koehler and his colleagues used the neutron beam to measure 'neutron resonances' in each of four different isotopes of platinum. The resonances are particular energies at which the neutrons are especially likely to be absorbed by the platinum nuclei. The motion of protons and neutrons inside the platinum nuclei affects the pattern of resonances. And according to random matrix theory, a mathematical theory that for decades has been crucial for calculating the behaviour of large nuclei, those motions should be chaotic.;
Yet, as Koehler and his colleagues report this month in Physical Review Letters (P. E. Koehler et al. Phys. Rev. Lett. 105, 072502; 2010), their analysis of the ORELA data found no sign that the nucleons in platinum were moving chaotically. By looking at the strength of the resonances, rather than just their spacing, the group rejects the applicability of random matrix theory with a 99.997% probability. Instead, the nucleons seem to move in a coordinated fashion. "There's no viable model of nuclear structure that could explain this," says Koehler.
The description of the results is compatible with the Alpha Module Model of nucler structure. Neutrons and protons form spin pairs; neutron-neutron, proton-proton and neutron-proton. But a neutron can form a spin pair with only one other neutron and with one proton, and likewise for a proton. This leads to chains of modules of the form -n-p-p-n-, or equivalently -p-n-n-p-, and these close to form rings in shells. These rings rotate in four modes; as a vortex ring, like a wheel and like a flipping coin about two perpendicular ax tes. The end result is the nucleons are smeared over a spherical shell and a nucleus dynamically appears to be made up of concentric spherical shells.
There is vast evidence for the Alpha Module Model of nuclear structure in terms of the statistical analysis of the binding energies of nuclides. In particular the evidence establishes that neutrons repel each other through the so-called nuclear strong force but are attracted to protons. The same applies to protons. Nuclei are held together primarily by the formation of spin pairs. See Nucleus for a brief introduction.
HOME PAGE OF Thayer Watkins