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Re: Articles

Original poster: Jim Lux <jimlux@xxxxxxxxxxxxx>

At 01:40 PM 2/26/2006, Tesla list wrote:


Supposedly fusion power has been demonstrated using piezo-electric
crystals with HV excitation.  Won't power a city (now) but may be a
convenient source for penetrating charged and neutral particles.
This is a reputable "e-zine" so adds considerable credibility.

http://www.powermanagementdesignline.com/showArticle.jhtml?articleID=180205456
They may be reputable, but there's so many typographical errors and misleading statements in the article that it's amazing. 


"
Traditional portable neutron sources are at least a foot long and require a high-voltage power supply that can deliver 250,000 electron-volts 
"
The particles are accelerated to 250,000 eV (250keV), but power supplies are rated in "volts"
Hmm.. traditional sources a foot long and a couple inches in diameter vs 15x15 cm for the new one. The switch between customary and metric units obscures the fact that they're really about the same volume. The traditional source is long and skinny to fit down a well casing. 

A neutron source based on radioactive isotopes is much smaller than either.

"
we can use a battery to send just a few watts to heat the crystal to get its high-voltage output 
"
Sure, but you don't get a heck of a lot of neutrons for that few watts. Most commercial applications of neutrons require reasonably high neutron fluxes to make whatever it is you're doing detectable. [each crystal heated with 10W for 350 seconds -> 7kJ to make an average of 138 counts in 120 seconds, or roughly one count/second (about 5-6 times the background) into a 7.6 cm detector 10cm away. Even allowing for the 0.4 stated efficiency of the detector, and the solid angle intercepted by the detector, you're not talking about a huge neutron flux.
Not that these folks haven't done some interesting work, but this sort of "breathless, excited" reporting of something that's really pretty mundane doesn't benefit us much in the long run. It also tends to make people cynical, so that when something really interesting and valuable is reported, everyone goes, "oh yeah, same old hype".