From: Michael M. Butler (mmb@spies.com)
Date: Thu Feb 20 2003 - 20:45:44 MST
Hal Finney wrote:
> One possible explanation of the difference that occurs to me is that the
> original report apparently used dental machine X-rays, while LLNL used
> a third generation X-ray beam, their "Advanced Photon Source", which
> sounds pretty damn fancy, not to mention it's 100,000 times stronger.
> Maybe differences in the triggering radiation could explain the different
> results.
If I had a nickle for every time someone "reproduces" an experiment in the physical
sciences while *changing* big parts of it, I'd be independently wealthy.
I think there's a funny kind of elitist/NIH/knowitall circuit at work. At a minumum
I wish they'd summarize experimental/methodological differences in the precis or
in a sidebar near the conclusion. Then one could, if warranted, pck that list apart
for completeness, too.
<sarcasm>
It's a big expensive honker; those peons should be flattered that LLNL deigned
to even dismiss their results.
</sarcasm>
www.aps.anl.gov wasn't responding when I tried it. Google's cache worked, though:
http://216.239.33.100/search?q=cache:TjO9EorjG9AC:www.anl.gov/OPA/Frontiers2000/c1facil.html+%22Advanced+Photon+Source%22&hl=en&ie=UTF-8øì8
Excerpting:
Researchers from around the world are using Argonne’s Advanced Photon Source (APS)
to see their experiments through new eyes. The nation’s most brilliant X-ray beams
for materials science research, funded by the U.S. Department of Energy’s Office of
Basic Energy Sciences, has opened new doors for scientists in many different fields.
The 1,104-meter circumference APS, large enough to house a baseball park in its
center, is a complex of machines and devices that produce, accelerate and store
a beam of subatomic particles that is the source of APS X-ray beams. Researchers
have formed groups, called collaborative access teams, to add instruments to enhance
various types of research at the APS.
During 1998, the APS increased its brilliance, improved the particle beam’s vertical
stability, and developed a new method for maintaining a constant level of current in
the storage ring. These improvements have made the beam 10 times more brilliant than
its original specifications, and the particle beam’s vertical stability three times
better than its design goal.
The new method of accelerator operation, called top-up, will maintain a constant
level of current in the storage ring. Top-up operation can also maintain constant
heat load on X-ray optics and storage ring components, maintain constant power
demands on radio frequency generators, and send a constant signal strength to
beam-position monitors.
The second user beam run during 1999 showed the increasing reliability of APS beam
performance. Beam was available 95.6 percent of scheduled time during the 841-hour
run, and unscheduled beam loss occurred only once every 42 hours.
These high-quality, reliable X-ray beams at the APS have brought about new discoveries
in basic materials structure, encompassing industrial products, medical insights
and even archaeological information.
* A liquid isn’t always a liquid
* Particle dynamics in condensed matter revealed
* Changes in hair can indicate presence of breast cancer, APS researchers find
* New techniques for mammography promised
* Key asthma and allergy molecule pictured
* Measles, mumps are cousins to HIV, Ebola and influenza
* New techniques developed to measure phonons
* Examining an ancient figurine
* SBC: Every picture tells a story in Argonne’s Structural Biology Center
* Clay crystallization studies may lead to new catalysts
* Physicists collaborate to create a next-generation light source
For more information please contact Catherine Foster at 630-252-5580
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