Newsgroups: sci.military.moderated
From: "Paul F Austin" <paustin@digital.net>
Subject: Re: Range of nuke in vacuum
Date: Wed, 21 Jul 1999 18:20:00 GMT

Pavel Podvig wrote in message ...
>Renato Croci wrote in message ...
>>I think this was the original reason for the development of the "neutron
>>bomb", originally intended as ABM warhead.
>
>When the Soviet Union was working on its first ABM program, it tested two
>types of warheads for its interceptors. One had enhanced neutron yield, the
>other one had enhanced X-ray yield. The latter proved much more efficient.
>According to the chief designer of the Moscow ABM system, the primary kill
>mechanism was the shock wave that resulted from X-ray absorbtion by the
>warhead surface. Sure, we are talking about mechanical damage here, not the
>damage to electronic components or the nuclear charge.


That isn't exactly right. An intense X-ray fluence causes thermo-mechanical
shock in high-atomic weight (high-Z) materials and reentry vehicle bodies
are made of carbon composites mostly. The shock occurs in the high Z (like
Pu and U) materials and breaks them. Light atomic weight materials like
carbon, aluminum and berillium are less susceptable.

High-Z materials absorb X-rays strongly and the X-ray gradient set up by
that absorption causes differential heating. The differential heating
translates into differential (very high) thermal expansion rates along the
direction of propagation of the X-ray front which becomes shock in the body
of the material. The shock propagates to the back side of the material where
it becomes a rarefaction that causes the material to fail in tension with a
scab flying off the back side, much the way a HESH warhead works.

This differential heating is so strong that given a high enough X-ray
fluence, the difference in energy absorption across a gold bond wire about
1mil in diameter can be enough to destroy the wire.

Conscience, that quiet voice that says "Someone may be watching"

Paul F Austin
paustin@digital.net