From: "Jeff Greason" <jgreason@hughes.net>
Newsgroups: sci.space.policy
Subject: Re: Orion vs Saturn V (was: Re: HMX )
Date: Mon, 11 Sep 2000 09:04:30 -0700

Henry Spencer <henry@spsystems.net> wrote in message
news:G0osr3.HrK@spsystems.net...
> In article <20000909174704.29365.00000219@nso-ba.aol.com>,
> Azt28 <azt28@aol.com> wrote:
> >Why never speak about metastable nuclei able to release up to
> >400 kev of gamma rays?
>
> Probably because actual information on these alleged metastable nuclei
> seems to be hard to come by.
>
> >When in space, these materials may be used as igniter of a fusion
> >bomb without any fission element.
>
> Care to explain how gamma rays can be used for bomb ignition?  (Normally
> soft X-rays are used; there is a big difference.)

There are potential isomeric transitions which could, in principle, be
sources for gamma rays down to a few 10's of keV.  However, getting
them to come out with any significant beam strength is the old, old problem
of the gamma ray laser -- namely that the isomers with sufficiently long
lifetimes to make it practical to assemble your laser medium have, by
necessity, *very* narrow linewidths, and it's very difficult to keep your
linewidths from being doppler-broadened when your laser medium is
in the process of self destructing :-)

In other words, "metastable nuclei" -- i.e., those with long-lived
isomeric transitions, could *in principle* be used as a source for low
energy gamma rays.  These could *in principle* substitute for a fission
explosion as a source for compression of fusion fuel prior to ignition.
However, the practical problems are so great that I wouldn't hold my
breath.

----------------------------------------------------------------
"Limited funds are a blessing, not         Jeff Greason
a curse.  Nothing encourages creative      President & Eng. Mgr.
thinking in quite the same way." --L. Yau  XCOR Aerospace
   <www.xcor-aerospace.com>                <jgreason@hughes.net>