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<DIV><FONT face="Lucida Sans Unicode" color=#000080 size=2><A
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<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=qualiall@union.org.za href="mailto:qualiall@union.org.za">Kevin
Robert Dean</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=lbo-talk@lbo-talk.org
href="mailto:lbo-talk@lbo-talk.org">lbo-talk@lbo-talk.org</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Thursday, August 14, 2003 8:22
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> [lbo-talk] New WMDs</DIV>
<DIV><BR></DIV>Gamma-ray weapons<BR><BR>AN EXOTIC kind of nuclear explosive
being developed by the<BR>US Department of Defense could blur the
critical<BR>distinction between conventional and nuclear weapons. The<BR>work
has also raised fears that weapons based on this<BR>technology could trigger
the next arms race.<BR><BR>The explosive works by stimulating the release of
energy<BR>from the nuclei of certain elements but does not involve<BR>nuclear
fission or fusion. The energy, emitted as gamma<BR>radiation, is thousands of
times greater than that from<BR>conventional chemical explosives. The
technology has<BR>already been included in the Department of
Defense's<BR>Militarily Critical Technologies List, which says:
"Such<BR>extraordinary energy density has the potential to<BR>revolutionise
all aspects of warfare."<BR><BR>Scientists have known for many years that the
nuclei of<BR>some elements, such as hafnium, can exist in a
high-energy<BR>state, or nuclear isomer, that slowly decays to a<BR>low-energy
state by emitting gamma rays. For example,<BR>hafnium178m2, the excited,
isomeric form of hafnium-178,<BR>has a half-life of 31 years.<BR><BR>The
possibility that this process could be explosive was<BR>discovered when Carl
Collins and colleagues at the<BR>University of Texas at Dallas demonstrated
that they could<BR>artificially trigger the decay of the hafnium isomer
by<BR>bombarding it with low-energy Xrays (New Scientist, 3 July<BR>1999,
p42). The experiment released 60 times as much energy<BR>as was put in, and in
theory a much greater energy release<BR>could be achieved. <BR><BR>Before
hafnium can be used as an explosive, energy has to<BR>be "pumped" into its
nuclei. Just as the electrons in atoms<BR>can be excited when the atom absorbs
a photon, hafnium<BR>nuclei can become excited by absorbing high-energy
photons.<BR>The nuclei later return to their lowest energy states
by<BR>emitting a gamma-ray photon. Nuclear isomers were<BR>originally seen as
a means of storing energy, but the<BR>possibility that the decay could be
accelerated fired the<BR>interest of the Department of Defense, which is
also<BR>investigating several other candidate materials such as<BR>thorium and
niobium.<BR><BR>For the moment, the production method involves
bombarding<BR>tantalum with protons, causing it to decay
into<BR>hafnium-178m2. This requires a nuclear reactor or a<BR>particle
accelerator, and only tiny amounts can be made.<BR>Currently, the Air Force
Research Laboratory at Kirtland,<BR>New Mexico, which is studying the
phenomenon, gets its<BR>hafnium-178m2 from SRS Technologies, a research
and<BR>development company in Huntsville, Alabama, which refines<BR>the
hafnium from nuclear material left over from other<BR>experiments. The company
is under contract to produce<BR>experimental sources of hafnium178m2, but only
in amounts<BR>less than one ten-thousandth of a gram. <BR><BR>But in future
there may be cheaper ways to create the<BR>hafnium isomer - by bombarding
ordinary hafnium with<BR>high-energy photons, for example. Hill Roberts,
chief<BR>scientist at SRS, believes that technology to produce
gram<BR>quantities will exist within five years. The price is<BR>likely to be
high- similar to enriched uranium, which costs<BR>thousands of dollars per
kilogram- but unlike uranium it<BR>can be used in any quantity, as it does not
require a<BR>critical mass to maintain the nuclear reaction.<BR><BR>The
hafnium explosive could be extremely powerful. One gram<BR>of fully charged
hafnium isomer could store more energy<BR>than 50 kilograms of TNT. Miniature
missiles could be made<BR>with warheads that are far more powerful than
existing<BR>conventional weapons, giving massively enhanced firepower<BR>to
the armed forces using them.<BR><BR>The effect of a nuclear-isomer explosion
would be to<BR>release high-energy gamma rays capable of killing any<BR>living
thing in the immediate area. It would cause little<BR>fallout compared to a
fission explosion, but any<BR>undetonated isomer would be dispersed as small
radioactive<BR>particles, making it a somewhat "dirty" bomb. This
material<BR>could cause long-term health problems for anybody who<BR>breathed
it in. <BR><BR>There would also be political fallout. In the 1950s, the
US<BR>backed away from developing nuclear mini-weapons such as<BR>the "Davy
Crockett" nuclear bazooka that delivered an<BR>explosive punch of 18 tonnes of
TNT. These weapons blurred<BR>the divide between the explosive power of
nuclear and<BR>conventional weapons, and the government feared
that<BR>military commanders would be more likely to use nuclear<BR>weapons
that had a similar effect on the battlefield to<BR>conventional weapons. By
ensuring that the explosive power<BR>of a nuclear weapon was always far
greater, it hoped that<BR>they could only be used in exceptional circumstance
when a<BR>dramatic escalation of force was deemed necessary. <BR><BR>Then in
1994, the US confirmed this policy with the<BR>Spratt-Furse law, which
prevents US military from<BR>developing mini-nukes of less than five kilotons.
But the<BR>development of a new weapon that spans the gap between
the<BR>explosive power of nuclear and conventional weapons would<BR>remove
this restraint, giving commanders a way of<BR>increasing the amount of force
they can use in a series of<BR>small steps.<BR><BR>Nuclear-isomer weapons
could be a major advantage to armies<BR>possessing them, leading to the
possibility of an arms<BR>race. <BR><BR>AndrZ Gsponer, director of the
Independent Scientific<BR>Research Institute in Geneva, believes that a
nation<BR>without such weapons would not be able to fight one
that<BR>possesses them. As a result, he says, "many countries which<BR>will
not have access to these weapons will produce nuclear<BR>weapons as a
deterrent", leading to a new cycle of<BR>proliferation.<BR><BR>The Department
of Defense notes that there are serious<BR>technical issues to be overcome and
that useful<BR>applications may be decades away. But its
Militarily<BR>Critical Technologies List also says: "We should
remember<BR>that less than six years intervened between the
first<BR>scientific publication characterising the phenomenon of<BR>fission
and the first use of a nuclear weapon in 1945." <BR><BR><BR>###<BR>New
Scientist issue: 16th August 2003 <BR><BR>Author: David Hambling<BR><BR>PLEASE
MENTION NEW SCIENTIST AS THE SOURCE OF THIS STORY<BR>AND, IF PUBLISHING
ONLINE, PLEASE CARRY A HYPERLINK TO:<BR><A
href="http://www.newscientist.com">http://www.newscientist.com</A>
<BR><BR>---<BR>Sent from UnionMail Service
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