http://ptonline.aip.org/journals/doc/PHTOAD-ft/vol_63/iss_2/10_1.shtml?bypassSSO=1
Physics Today
Letters
Muons, deuterium, and cold fusion
February 2010, page 10
It would be in the national interest for all those involved in the
cold-fusion
controversy to read a 1957 paper by Luis Alvarez and his
coworkers. During the
1950s Alvarez, of the University of California,
Berkeley, invented a new kind
of particle detector. Called a hydrogen
bubble chamber, it was the subject of
one of the 40 patents he held.
It was vastly superior to other detectors then
available, and it
permitted experiments that would not otherwise have been
possible.
Using his detector, in 1957 Alvarez observed the capture of μ− mesons by
deuterium molecules, immediately followed by the nuclear
fusion of the
two deuterium atoms. He reported his discovery in one of
the 168 scientific
publications he wrote; he described the process as
the chemical catalysis of
nuclear fusion.1 The force holding two atoms
together in a diatomic molecule is linear in the
mass of the electron.
Substituting a μ− meson for an electron effectively increased that force more
than 200 times,
allowing the fusion to occur.
Although Alvarez used cyclotron-produced μ− mesons, Earth is continually bathed
in cosmic rays that produce μ mesons and other particles.. By showing that a μ−
meson will induce fusion of two deuterons if it is captured in their
electric
field, Alvarez proved that a molecule of deuterium exposed to
the terrestrial
cosmic-ray background has a small but finite
probability of undergoing fusion.
In 1989 Martin Fleischmann and Stanley Pons also discovered the
fusion of
deuterium without the use of great heat and called a press
conference to
announce their “cold fusion” results. The media was
quick to pounce on the promise of nearly unlimited power
from such
small equipment, but the scientific community was much more
skeptical.
The fusion of two deuterons requires hundreds of thousands of eV,
whereas Pons and Fleischmann’s experiment involved only a few volts, a
fact that rendered their explanation
of the effect impossible. Still,
since 1989 the Pons–Fleischmann experiment has been repeated over and
over, 2 often with the result that rather more energy is released than can be
explained
by the equipment used. The 24 April 2009 segment of the CBS
TV show 60 Minutes rehashed those experiments and again mentioned the potential
for nuclear-powered
vehicles and other wonderful applications.
It takes hundreds of MeV to make a meson, which has a half-life of
only microseconds and produces at most only a
few tens of MeV of
energy during the fusion reaction. Had any viable
energy-producing
application come out of the effect he discovered, Alvarez
would have
patented it. If those involved in the cold-fusion controversy read
Alvarez’s paper, they will recognize that deuterium does undergo fusion
if exposed to
cosmic-ray secondaries. Can the cold-fusion results be
explained merely in
terms of fusion induced by naturally occurring
cosmic-ray muons, or is
something else going on in those experiments?
References
1. 1. L.. Alvarez, Phys. Rev. 105, 1127 (1957) [SPIN].
2. 2. See, for example, the review by G. K. Hubler, Surf. Coat. Technol.
201, 8568 (2007) [INSPEC].
Jacques Read
([email protected])
Washington, DC
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