Re: plutonium natural abundance

[MCNAUGHT@Lanl.GOV (Mike McNaughton)]

>So what is the natural abundance 0.005%, 0.0005% .... what???
>     
I have a copy of "the Transuranium Elements" by Glenn T. Seaborg, published
by Yale University Press, 1958.  Seaborg describes how, after his discovery
of plutonium in 1940, he and M. Perlman working at Berkeley found naturally
produced plutonium in pitchblende and monazite, and extracted microgram
quantities of plutonium from pitchblende in 1942. He includes a table giving
the ratio of plutonium to uranium in various samples as follows.
Canadian pitchblende: 7E-12
Belgian Congo pitchblende: 12E-12
Colorado pitchblende: 8E-12
Brazilian monazite: 8E-12
North Carolina monazite: 4E-12
He explains the natural production of plutonium as follows.
(alpha,n) reactions produce neutrons, which are absorbed by U-238 to produce
U-239; then U-239 decays to Pu-239.  Variation among the different samples
results from the presence of different neutron absorbing substances.

Mike McNaughton, Los Alamos
MCNAUGHT@LANL.GOV