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A comment on Australians Scour Desert for Dangerous Radioactive Capsule Smaller Than a Penny. Parent comment

Re:Australians Scour Desert for Dangerous Radioactive Capsul... by bonzini on Sunday January 29, 2023 @04:47PM (#34573100)
300 Ci is 11 TBq (terabecquerel), or 11·10^12 decays per second. Co-60 has a half life of 166 million seconds, so it was 11·166·10^18/ln 2 atoms=2.6·10^21 atoms, which is 0.004 moles (a mole is 6.02·10^23 atoms).

A mole of cobalt 60 weighs 60 g, so it was a quarter of a gram if I did the calculations right.

The ln 2 factor is because the probability of a decay happening in a second is ln 2 divided by the half life.

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Re:Australians Scour Desert for Dangerous Radioactive Capsul... by moffkalast on Sunday January 29, 2023 @07:06PM (#34574179)
> 166 million seconds

Or 5,2 years

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Re:Australians Scour Desert for Dangerous Radioactive Capsul... by bonzini on Monday January 30, 2023 @06:36AM (#34578451)
Yeah but becquerels are #decays per second, so I need the probability of a decay happening in a second, not in a year. :) Sooner or later the dreaded multiply by 86400*365 will happen.
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