RE: Real Cold Fusion

["Franta, Jaroslav" <frantaj@aecl.ca>]

 Jacques.Read@eh.doe.gov [mailto:Jacques.Read@eh.doe.gov] wrote on Tuesday
August 15, 2000 3:04 PM

Perhaps one reason why people were more gullible about cold fusion was that
Luis
Alvarez at Berkeley published in 1957 the discovery of mu-meson catalyzed
deuterium fusion.  His group had observed tracks in a liquid hydrogen bubble
chamber that showed a mu-minus meson being stopped and captured by a D-D
molecule.  The muon, as a negative lepton, replaced an electron, but having
450
times the mass was able to bind the two deuterium nuclei together with 450
times
the force.  The vibrational modes of the molecule were enough to defeat the
Coulomb barrier in a few vibrations, and fusion resulted.  In some
instances,
the same muon was able to catalyze several molecules before decaying.
Unfortunately, muons are short-lived, so nothing commercial ever came out of
it,
but the effect exists.  (Also, of course, the 20 MeV per fusion pay-back
isn't
enough to support the several hundred MeV needed to make the muon.)
<><><><><><><><>

Here's the latest news on this topic ( its been a while !! ), courtesy of a
colleague :

http://www.newscientist.com/news/news.jsp?id=ns225443
>From New Scientist magazine, 02 September 2000.
The big squeeze
Source: Physics Review Letters (vol 85, p1674) 
Eugenie Samuel 
Can a tiny particle make fusion work where giant machines have failed? 
TRYING to extract limitless amounts of energy from nuclear fusion has proved
tantalisingly difficult. Scientists are still struggling with huge reactors
capable of containing the temperatures and pressures needed to make nuclei
fuse. But there is another way: persuading a particle called a muon to
squeeze together adjacent nuclei. 
Muon-catalysed fusion has faced two big hurdles. Now an international team
has cracked one of these, with a nifty way to bump up the number of nuclear
reactions each muon achieves before it decays. Meanwhile, a group of
Japanese physicists is making progress on the other. 
The muon aids fusion by first replacing an electron orbiting around a
tritium nucleus--a heavy isotope of hydrogen--forming muonic tritium. If a
deuterium nucleus is added, this creates a compound molecule. The muon, now
orbiting the whole compound molecule, squeezes the two nuclei closer
together until they fuse and become a helium nucleus, otherwise known as an
alpha particle (click on thumbnail graphic for Diagram). 
Because the muon does the squeezing, there is no need for high temperatures
and pressures. The researchers are reluctant to use the name "cold fusion"
for their technique. "But it's colder than anything else going," says team
leader Glen Marshall of the TRIUMF particle physics lab in Vancouver,
British Columbia. 
In order to get a decent yield, the energy of the muonic tritium must be
kept very low, about 1 electronvolt (eV), as it approaches the deuterium
nuclei. In earlier work, researchers had used a scattergun approach, firing
particles with different energies at a deuterium target. But Marshall's team
discovered that muonic tritium escapes from a tritium-hydrogen mixture when
its energy is about 1 eV. "That was a coincidental discovery," admits
Marshall. "We used that fact to select atoms with the right kind of energy."

The researchers fired their beam of 1 eV muonic tritium at concentrated
deuterium condensed onto gold foil, and chilled the whole set-up to 3
kelvin. When they measured the number of fusions per muon by detecting the
alpha particles produced, they clocked up a rate a hundred times as high as
the scattergun approach. "It's a very interesting and important step," says
Ken Nagamine at the Japanese Institute of Physics and Chemical Research
(RIKEN) in Wako-shi. 
Nagamine's team is currently working on the other problem dogging muon
fusion. In a reactor core each muon must catalyse about 300 fusions before
its natural lifetime expires. The trouble is, the negatively charged muon
tends to stick to the positive alpha particle at the end of the reaction. 
Nagamine says that the muon can break free under the right conditions. "We
have discovered a process of high energy recoil of products which can strip
the muon from the alpha particle." 
<><><><><><><><><><>

Comment : 1 eV is not that bad - it corresponds to a temprature (in a gas of
randomly moving particles) of some 11,500 Kelvins -- that would give you
pretty high-quality steam, I think !

Jaro
frantaj@aecl.ca
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