Understanding Of Fission Research Articles

Visualizing Nuclear Scission through a Multifield Extension of Topological Analysis.

In nuclear science, density functional theory (DFT) is a powerful tool to model the complex interactions within the atomic nucleus, and is the primary theoretical approach used by physicists seeking a better understanding of fission. However DFT simulations result in complex multivariate datasets in which it is difficult to locate the crucial `scission' point at which one nucleus fragments into two, and to identify the precursors to scission. The Joint Contour Net (JCN) has recently been proposed as a new data structure for the topological analysis of multivariate scalar fields, analogous to the contour tree for univariate fields. This paper reports the analysis of DFT simulations using the JCN, the first application of the JCN technique to real data. It makes three contributions to visualization: (i) a set of practical methods for visualizing the JCN, (ii) new insight into the detection of nuclear scission, and (iii) an analysis of aesthetic criteria to drive further work on representing the JCN.

FtsZ and the division of prokaryotic cells and organelles

Binary fission of many prokaryotes as well as some eukaryotic organelles depends on the FtsZ protein, which self-assembles into a membrane-associated ring structure early in the division process. FtsZ is homologous to tubulin, the building block of the microtubule cytoskeleton in eukaryotes. Recent advances in genomics and cell-imaging techniques have paved the way for the remarkable progress in our understanding of fission in bacteria and organelles.

Why should we investigate nuclides far off the stability line

An analysis of the nuclear chart shows that there should exist more beta-instable nuclides (including neutron-, proton- and alpha-emitters) than hitherto observed. The half-lives of these radioactive nuclides fall in the region 10 −3–10 2 sec which is the experimental reason that they have not been studied very much so far. It is emphasized that new double magic regions will be found among these nuclides as well as new regions of stable deformation. Q β -values far off the stability line as well as a careful mapping of delayed neutron- and proton-emitters and alpha emitters will be of great importance for the semi-empirical mass formula. In addition half-lives and neutron separation energies are of astrophysical interest. Because of the high Q β -values expected, highly excited states will be populated and beta decay yields information which usually is reserved for nuclear reactions. The extension of the systematics of fission and spallation yields into the regions of very short half-lives may increase our understanding of fission as well as other nuclear reaction processes. The experimental study of these short-lived nuclides requires new experimental approaches which are discussed in the next paper.