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Re: China approves supercollider
At 11:45 PM 2/16/98 -0600, Sandy Perle wrote:
>This supercollider is now the 4th in the world, all on European
>and Asian soil. Just another sad example of US technology going
>nowhere!
> BEIJING, Feb 16 (AFP) - China's first large nuclear fusion
>installation has passed appraisal from the nation's top physicists and
>will shortly go into operation, the China Daily reported Mpnday.
> The HT-7 Superconductive Tokamak was built in Hefei, capital of
>eastern Anhui province in 1995 by the Chinese Academy of Science
>Plasma Physics Institute.
> It is the world's fourth such installation with similar sites in
>France, Russia and Japan, the newspaper said.
> It is used to accelerate particles at ultra-high speeds with the
>aim of forcing two atoms to join together and create a nuclear fusion.
> China has a second nuclear fusion research centre in
>Chengdu, southwest China which focuses on theoretical research.
Dear Sandy, List members,
There is a considerable confusion here between a Tokomak Fusion machine and
a Supercollider. The latter is a high-energy machine which accelerates
particles up into the energy range of Tera-electronvolts (TeV) and allows
the study of particle reactions at these energies.
A Tokomak, on the other hand, imparts "thermal" energies of several tens to
hopefully 100 keV to a plasma of T and D ions in order to bring about the
T(d,n)He-4 reaction which has a dramatic resonance in the cross section at
100 keV. The reaction products are stable and the Q-value is almost 18
MeV. The U.S. has a Tokomak at the Priceton Plasma Physics Laboratory,
although I don't think it uses superconducting magnets, at least it did not
use to.
For my work, I once built an accelerator of 180 kV to study the
polarization transfer from a polarized deuteron to the neutron in the
T(d,n)He-4 reaction. A 100-200 kV machine is all you need by way of an
accelerator to achieve that kind of fusion.
By the way, at supercollider energies the reaction has a minute
cross-section and both reaction products n + He-4 would be highly unstable.
Also, the total energies involved lie in the range of hundreds to
thousands of GeV, i.e., astronomically higher than the negligible Q-value.
Fritz Seiler
*************************
Fritz A. Seiler
Principal
Sigma Five Associates
P.O. Box 14006
Albuquerque, NM 87191,USA
Tel: xx-505-323-7848
Fax: xx-505-293-3911
e-mail: faseiler@nmia.com
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