Nuclide Relief

3558 ground states from NUBASE2020, plotted on N (neutrons, across) and Z (protons, into depth).

Height

Height is ΔE = M(Z,A) − min_Z M(Z,A): how far each nucleus sits above the most bound isobar, 0 to 104 MeV. Stable nuclei lie on the floor; each A-slice is a mass parabola.

Colour

Discovery year

Colour marks the year each isotope was first identified. Grey marks a stable nuclide whose element was already known but whose isotope had not yet been resolved: iron was worked for millennia, ⁵⁶Fe was resolved by Aston in 1923.

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Rendering

Masses, half-lives and discovery years: Kondev et al., Chin. Phys. C 45, 030001 (2021), NUBASE2020. Decay mode is the first-listed branch; ββ emitters such as ⁴⁸Ca are drawn as β⁻. B/A uses the tabulated mass excess, with systematic (#) values included and marked.

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