RE: Chart of the Nuclides

["Frame, Paul" <FRAMEP@ORAU.GOV>]

> Does anyone know the anedotal story of how Emilio Sergre 
> proposed the Chart
> of the Nuclides?
> 
> Jeff Ching	[ching.jeff@email.mcclellan.af.mil]
> Mcclellan Nuclear Radiation Center

Quoting from "A Mind Always in Motion: the Autobiography of Emilio Segre"
1993, Univ of California Press.

"Tables of natural radioactive isotopes go back to Curie, Rutherford and
their colleagues. With the discovery of artificial radioactivity, they
became much larger. A first one was drawn up in Rome by our group and by G.
Fea. I drew a useful diagram, following Heisenberg, while still in Rome." 

It would seem that what Segre calls a "useful diagram" is the chart of the
nuclides. The time period he is referring to is ca 1935.

He was working with Fermi when the latter conceived the idea of producing
new radionuclides via neutron activation. Fermi was producing an immense
number of these new artificial radionuclides and it would seem natural to
try to organize them in some fashion similar to the periodic table.  Segre
was at the right place at the right time.

The oldest one I actually have (1947) is titled "The Segre Chart" and
published by Addison-Wesley Press.

At the time, (1930s)almost every property of a nuclide was being plotted
against the atomic mass or atomic mass number  e.g., atomic weight vs
position (Group #) on the periodic table.  In the second edition of
"Radioactivity" (1938) by Hevesy and Paneth, there is something that looks
very much like Segre's chart (at least the later versions) except Hevesy and
Paneth (who would have known Segre) plot mass # minus twice the atomic #
versus the atomic number.

None of this indicates what form the original chart took but I hope it at
least provides a partial answer to your question.

Best wishes

Paul Frame
Professional Training Programs
ORAU
framep@orau.gov
http://www.orau.gov/ptp/ptp.htm




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