From: Robert J. Bradbury (bradbury@aeiveos.com)
Date: Mon Oct 14 2002 - 15:19:06 MDT
On Mon, 14 Oct 2002, Robert J. Bradbury wrote:
>
> On Mon, 14 Oct 2002, Samantha Tennison wrote:
>
> > There is now growing evidence
> > that "red mercury" nukes have been developed which
> > enable 2 megaton bombs to be the size of baseballs.
>
> Can we have some evidence here? What is this "red mercury"
> stuff? (I know I've heard the phrase before but I'm
> unfamiliar with any physics that makes it reasonable
> that you can get a 2 MT bomb the size of a baseball.)
Aha, I answered my own question (or the great Google did
but I typed it in...):
Red Mercury seems to be an urban legend without much
substance to it:
http://www.eng-tips.com/gviewthread.cfm/lev2/19/lev3/64/pid/466/qid/26894
Interestingly it does beg an answer to my earlier question
as to whether there is a material other than U-235 or Pu-239
that can make a nuclear weapon with less material. U-235
decays releasing an alpha particle with ~4.7 MeV while
Pu-239 decays with an alpha particle with 5.2 MeV. Other
isotopes like Am-241;-2433 (alpha, 5.4-6 MeV) and Cm-242/3/4/5/6/7,
alpha, 5.3-6.2 MeV) would seem to be likely candidates.
Some of those isotopes seem to be much nicer choices as they
have half lives in the days to years time frame rather than
the tens of thousands to millions of years. So I suspect
they would go "poof" with quite a bit less material involved.
Anyone enough of a nuclear engineer to know what the critical
parameters are? Is it rate of alpha particle production?
Or perhaps neutron capture rates (thermal neutron cross section???).
Also -- nuclear reactions as I was taught them were based on
an exponential rate in the increase of neutron production
(alpha particles shouldn't be able to enter a nucleus) --
how does the release of an alpha particle get translated into
neutrons? (Does the alpha particle itself decay very quickly?).
Robert
(The source for any of the figures used above is the Handbook
of Chemistry and Physics, Chapter 11).
of
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