Re: Chart of the Nuclides

["Dale E. Boyce" <dale@radpro.uchicago.edu>]

Cs-135 has a 3E6 year half life Cs-137 only 30 years.  Given the same
number of atoms produced for each you get 1/100000 the activity for
Cs-135.  The mass yield of 135 is slightly greater than 137 so you
get slightly more atoms of 135, but much less activity of Cs-135 than
Cs-137.

The magic number is a reference to Cs-137's filled neutron shell, 82
represents completion of a shell in nuclear structure.  The bolded
columns and rows indicate filled shells.

Xe-135 is an interesting wild card.  It has a huge neutron capture
cross section, and has the potential to prevent a reactor from
staying critical.  However, it has no effect on the mass yield listed
in the table.