Talk:Calcium-48
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Half-life inconsistency
[edit]The calcium-48 article mentions a half-life of 4.3 × 1019 years. Because no uncertainty is specified, that would implicitly mean (4.3 ± 0.1) × 1019 years. The cited source (Balysh et al.) gives a much larger uncertainty of (4.3 ( 2.4 −1.1 stat.) (± 1.4 syst.)) × 1019 years. It would appear that the source has been grossly misquoted.
The article on isotopes of calcium gives a half-life of (5.3 ± 1.7) × 1016 years.
In short, this is a mess. I'll correct as soon as I can find a reliable source.
—Herbee 13:38, 22 January 2007 (UTC)
- I don't think that there is a more reliable source than the original paper, of which you can find a preprint here. Icek 17:42, 12 November 2007 (UTC)
Is there any reference concerning a physical accumulation process whereby EE20Ca48 with 20 deuterons plus 8 extra neutrons was able to be exposed to and accumulate 8 excess neutrons? S process or R process or whatever?WFPM (talk) 22:51, 9 August 2012 (UTC)
decay mode
[edit]This entry states that "the only radioactive decay pathway open to it is the extremely rare process of double beta decay." However, the isotope table in the main calcium entry lists single beta decay as a possible (but not yet observed) decay pathway. 69.72.92.221 (talk) 06:50, 1 December 2015 (UTC)
- The single beta decay of 48Ca is fourth-forbidden and has a low Q-value of about 0.15 MeV, and is hence slowed down by a factor of about 1019 (here is a nice discussion of this). So yes it is possible, but in practice it is so hindered that double beta decay is actually faster; the same thing happens for 96Zr. You are nevertheless correct and I will update the article accordingly. Double sharp (talk) 04:57, 22 March 2018 (UTC)
- Changed to "Although it is unusually neutron-rich for such a light nucleus, its beta decay is extremely hindered, and so the only radioactive decay pathway that it has been observed to undergo is the extremely rare process of double beta decay." Double sharp (talk) 05:00, 22 March 2018 (UTC)