) whilst over this item in the SELECTOR menu produces a Segre plot of the energy either for or against alpha decay. Negative values indicate a reluctance against alpha decay (it is stable to alpha decay) and positive values a propensity for alpha decay (it is pre-disposed to alpha decay). If positive, this is the total amount of energy that would be released by the decay. If negative, this does not mean that the nuclide WILL decay by alpha decay; if the difference is less that 2MeV it is highly unlikely to decay by alpha decay because of the large coulombic barrier against alpha decay.
Pressing the RH mouse button (
) similarly produces a Segre chart colour coded by the energy for and against beta decay, with negative values indicating a stability against beta decay, and positive values a propensity for beta decay (or inverse beta decay). If positive, this is the total amount of energy that would be released by the decay. With beta/inverse beta, there is no large coulombic barrier to penetrate, so if it can decay, it probably will, given time. In this mode, the odd/even effect is prominently evident throughout the chart.
Pressing the MID mouse button (+) similarly gives a Segre chart colour coded by energy for or against both beta and alpha decays together. Pressing both RH and LH mouse buttons together gives exactly the same chart. Other combinations of buttons have no other effects.
These charts are similar to thode produced by the 'L H S STAB' and the 'Z A N BEmax' modes, but they show the MAGNITUDE rather than just the SIGN of the stability. They thus reveal features completely hidden by other representations.
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