[Phys-L] Re: Mr. Fusion

[Ludwik Kowalski <kowalskil@MAIL.MONTCLAIR.EDU>]

On Thursday, Apr 28, 2005, at 08:21 America/New_York, John Denker wrote:

> Observation of nuclear fusion driven by a pyroelectric crystal
>       B. Naranjo, J.K. Gimzewski & S. Putterman
>        NATURE _434_ page 1115 (28 APRIL 2005)
>
> > While progress in fusion research continues with magnetic and
> > inertial confinement, alternative approaches such as Coulomb
> > explosions of deuterium clusters and ultrafast laser plasma
> > interactions also provide insight into basic processes and
> > technological applications. However, attempts to produce
> > fusion in a room temperature solid-state setting, including
> > cold  fusion and  bubble  fusion, have met with deep
> > scepticism7. Here we report that gently heating a pyroelectric
> > crystal in a deuterated atmosphere can generate fusion under
> > desktop conditions.  The electrostatic field of the crystal is
> > used to generate and accelerate a deuteron beam (>100 keV and
> > 4 nA), which, upon striking a deuterated target, produces a
> > neutron flux over 400 times the background level. The presence
> > of neutrons from the reaction D + D ==> 3He (820 keV) + n
> > (2.45 MeV) within the target is confirmed by pulse shape
> > analysis and proton recoil spectroscopy. As further evidence
> > for this fusion reaction, we use a novel time-of-flight
> > technique to demonstrate the delayed coincidence between the
> > outgoing a-particle and the neutron. Although the reported
> > fusion is not useful in the power-producing sense, we
> > anticipate that the system will find application as a simple
> > palm-sized neutron generator.

The most interesting part of this report (and the one below)
is generation of high potential differences by small  differences
in temperatures. I was familiar with piezoelectric, but not with
pyroelectric, crystals.

http://www.rpi.edu/~danony/Papers/
Electron%20and%20positive%20ion%20acceleration%20with%20pyroelectric%20c
rystals.pdf

Ludwik Kowalski
Let the perfect not be the enemy of the good.
**********************************************************

Below is the article of Kenneth Chang "Scientists in U.S.
create 'low-tech' nuclear fusion," published on page 7
of the "International Herald Tribune (4/29/05):

In a surprising feat of miniaturization, scientists reported
Thursday that they have produced nuclear fusion - the same
process that powers the sun - in a small cylinder just five
inches in diameter. And they say they will soon be able to
make the device even smaller.

While the 12-inch-long, or 30-centimeter-long, device is
probably too inefficient to produce electricity or other
forms of energy, the scientists say, egg-size fusion
generators could someday find uses in spacecraft thrusters,
medical treatments and scanners that search for bombs.

The findings, by a team at the University of California,
Los Angeles, led by Seth Putterman, are being reported in
the journal Nature.

The small fusion device accelerates hydrogen atoms and
slams them together to produce helium. Unlike earlier
claims of tabletop fusion - like "cold fusion," in 1989,
which suggested that energy could be produced by running
electricity through water and metal plates, and "sonofusion,"
in 2002, in which collapsing bubbles supposedly heat gases
to starlike temperatures - this claim is not being greeted
with skepticism.

"I think it's very persuasive," said William Happer, a
professor of physics at Princeton University.

Michael Saltmarsh, a retired scientist who worked at Oak
Ridge National Laboratory in Tennessee, said the energy of
the particles emitted by the collisions convincingly matched
what was expected for fusion. Saltmarsh was one of two Oak
Ridge scientists who said they were unable to detect the
signatures of fusion in the 2002 sonofusion experiment.

In a commentary accompanying the paper in Nature, Saltmarsh
described the new device as "intriguingly simple" and added,
"Indeed, in some ways it is remarkably low-tech."

By contrast with the earlier claims, the California researchers
do not assert that their invention will provide unlimited energy.
"What we've built so far," Putterman said, "no chance."

Indeed, the new device does not even produce enough energy to
warm the hand. But it could be useful as a source of neutrons,
the subatomic particles that are a byproduct of fusion. Because
neutrons do not have any electrical charge, they can penetrate
deep into matter, and that could provide a way to peer easily
into luggage or cargo containers.

"We can give them a little tiny front end for a camera that can
look behind things," Putterman said.

The central component of the device is a crystal of lithium
tantalate, which belongs to a class of materials known as
pyroelectrics. Pyroelectrics, which generate strong electric
fields when heated or cooled, have long been known, and were
possibly described as far back as 314 B.C. by a student of
Aristotle.

"It's quite a surprise to see it used in this way," said Happer.

In the experiment, the crystal was mounted inside the cylinder
and surrounded by deuterium gas, a heavy version of hydrogen.
Warming the crystal about 50 degrees Fahrenheit, or 10 degrees
centigrade, produced a charge of 1,000 volts. That created
electric fields around a tungsten tip that were so strong they
ripped electrons off the deuterium and accelerated the charged
deuterium ions into a target that also contained deuterium.
When one deuterium ion hit a deuterium atom, fusion occurred -
sometimes. But because only one in a million of the collisions
actually produce fusion, the device is an inefficient generator
of energy.

The jet of deuterium ions could serve as thrusters for small
spacecraft, and X-rays produced by electrons being caught in
the powerful electric fields might be useful for treating tumors.


NEW YORK In a surprising feat of miniaturization, scientists
reported Thursday that they have produced nuclear fusion - the
same process that powers the sun - in a small cylinder just
five inches in diameter. And they say they will soon be able
to make the device even smaller.

While the 12-inch-long, or 30-centimeter-long, device is probably
too inefficient to produce electricity or other forms of energy,
the scientists say, egg-size fusion generators could someday find
uses in spacecraft thrusters, medical treatments and scanners
that search for bombs.

The findings, by a team at the University of California, Los Angeles,
led by Seth Putterman, are being reported in the journal Nature.

The small fusion device accelerates hydrogen atoms and slams
  them together to produce helium. Unlike earlier claims of tabletop
fusion - like "cold fusion," in 1989, which suggested that energy
could be produced by running electricity through water and metal
plates, and "sonofusion," in 2002, in which collapsing bubbles
supposedly heat gases to starlike temperatures - this claim is not
being greeted with skepticism.

"I think it's very persuasive," said William Happer, a professor
of physics at Princeton University.

Michael Saltmarsh, a retired scientist who worked at Oak Ridge
National Laboratory in Tennessee, said the energy of the particles
emitted by the collisions convincingly matched what was expected
for fusion. Saltmarsh was one of two Oak Ridge scientists who said
they were unable to detect the signatures of fusion in the 2002
sonofusion experiment.

In a commentary accompanying the paper in Nature, Saltmarsh
described the new device as "intriguingly simple" and added,
"Indeed, in some ways it is remarkably low-tech."

By contrast with the earlier claims, the California researchers do not
assert that their invention will provide unlimited energy. "What we've
built so far," Putterman said, "no chance."

Indeed, the new device does not even produce enough energy to warm
the hand. But it could be useful as a source of neutrons, the subatomic
particles that are a byproduct of fusion. Because neutrons do not
have any electrical charge, they can penetrate deep into matter, and
that could provide a way to peer easily into luggage or cargo
containers.

"We can give them a little tiny front end for a camera that can look
behind things," Putterman said.

The central component of the device is a crystal of lithium tantalate,
which belongs to a class of materials known as pyroelectrics.
Pyroelectrics, which generate strong electric fields when heated or
cooled, have long been known, and were possibly described as far
back as 314 B.C. by a student of Aristotle.

"It's quite a surprise to see it used in this way," said Happer.

In the experiment, the crystal was mounted inside the cylinder and
surrounded by deuterium gas, a heavy version of hydrogen. Warming
the crystal about 50 degrees Fahrenheit, or 10 degrees centigrade,
produced a charge of 1,000 volts. That created electric fields
around a tungsten tip that were so strong they ripped electrons
off the deuterium and accelerated the charged deuterium ions into
a target that also contained deuterium.  When one deuterium ion
hit a deuterium atom, fusion occurred - sometimes. But because
only one in a million of the collisions actually produce fusion,
the device is an inefficient generator of energy.

The jet of deuterium ions could serve as thrusters for small spacecraft,
and X-rays produced by electrons being caught in the powerful electric
fields might be useful for treating tumors. The current device produces
only about 1,000 neutrons a second, few enough that it would not be
dangerous to use even in a physics demonstration, Saltmarsh said.
The researchers plan to create a more powerful version by replacing
deuterium in the target with tritium, an evenheavier form of hydrogen,
generating about 250 times as many neutrons.

Additional improvements should rase the rate to a million neutrons a
second. Commercial neutron generators, which can already make a
million neutrons a second, similarly accelerate deuterium into targets,
but they rely on high-voltage power sources to generate the electric
fields.

By relying on pyroelectric crystals instead, the new research could lead
to generators that are much simpler and less expensive.

What Putterman's made is an amazing little accelerator," Happer said.
"It's a version of that doesn't need any high high voltage."  Putterman
said he envisioned a device. consisting just of an egg-size container
with a crystal, deuterium gas and the target inside. Plunging the
container into ice water  or warming it with body heat would be enough
to set off the reactions. "We can diddle temperature a mere 30 degrees
and generate fields that make fusion,"  he said.
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