Nuclide stability

Using nuclide-stability rules, form a hypothesis that explains why calcium-40 should be a more stable nuclide than potassium-40. 

The overall development program included the study of other exchange materials such as niobates, zirconates, and tantalates, some of which had superior ion exchange and leaching properties, but were initially economically unattractive as compared to the titanates. These alternate materials will be briefly discussed along with applications to nuclide stabilization in other areas of nuclear processing. 

Allegorical representation of heavy nuclide stability, circa 1975, showing Figure 15.11 W. ., D] )t of the predicted half-lives of the heaviest nuclei. Note... 

The negative quantity in brackets is an irrational number known as the golden ratio, t = 0.61803. The solution Z = — iV(1.61803...) = — nuclide stability, as defined on both plots, converges to a point on the line r = Nx = r at A 267, the maxinum possible mass number for nuclides, stable against /1-type decay. By definition, this maximum,... 

To emphasize the periodicity of 8, suggested by the number spiral, the periodic table is rearranged as shown in Figure 4.5. Closure of the eleven periods coincides with the completion of electronic sub-levels, except for atomic numbers 62 and 94 that split the /-levels into sub-sets of 6 and 8. Additional structure, in complete agreement with the experimentally known sub-level order of the elements, is revealed by the zig-zag profiles that define the field of nuclide stability in Figure 4.4. 

Because the range of nuclidic stability is bounded by fractions that derive from Fibonacci numbers, it probably means that nuclear stability relates directly to the golden mean. To demonstrate this relationship it is noted that the plot of A vs Z, shown in figure 13 for the A(mod4) = 0 series of nuclides, separates into linear sections of constant neutron excess (A — 2Z) and slope 2. Each section terminates at both ends in a radioactive nuclide. The range of stability for each section follows directly from... 

Synthesis of further heavy nuclei is in progress at Berkeley, Darmstadt and Dubna. With regard to the search for the island of relatively high nuclide stability, target nuclei and projectile nuclei with closed shells and high neutron numbers are required. 

Regions of nuclide stability and predicted islands of relatively high stability contours of regions with ti/j > Is ----------, contours of regions with ti/2 > 1 h). 

The mass of a nucleus is less than the sum of the masses of its nucleons by an amount called the mass defect. The energy equivalent to the mass defect is the nuclear binding energy, usually expressed in units of MeV. The binding energy per nucleon is a measure of nuclide stability and varies with the number of nucleons in a nuclide. Nuclides with A == 60 are most stable. Lighter nuclei can join (fusion) or heavier nuclei can split (fission) to become more stable. 

What is the binding energy per nucleon Why is the binding energy per nucleon, rather than per nuclide, used to compare nuclide stability ... 

The fractional ratio of protons neutrons provides a refiable measure of nuclide stability and converges from unity to the golden ratio with increasing atomic mass. Rather than forming a smooth triangle, the limiting stability... 

The binding energy per nucleon is a measure of nuclide stability and varies with the number of nucleons. Nuclides with A 60 are most stable. 

This interpretation is supported [7] by analysis of the neutron imbalance of stable atomic species as a function of mass number, shown in Fig. 5. The region of nuclide stability is demarcated here by two zigzag lines with deflection points at common values of mass number A. Vertical hemlines through the deflection points divide the fleld into 11 segments of 24 nuclides each, in line with condition (c). This theme is developed in more detail in the paper on Atomic Structure in this volume. Defining neutron imbalance as either Z/N or (N — Z )jZ, the isotopes of each element, as shown in Fig. 6, map to either circular segments or straight lines that intersect where... 

Fig. 10 A plot of 1 -modular Farey sequences as a function of the natural numbers defines a set of infinite festoons that resembles the arrangement of nuclides in Figs. 5 and 7. The segment, obtained as a subset defined by limiting Fibonacci fractions that converge from 1 to r and subject to the condition A(mod4) = 0 —> 3, corresponds to the observed field of nuclide stability...

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