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Portable X-Ray Source Invented at MU

Posted: Sat Jan 12, 2013 1:48 pm
by bpaddock ... -the-hand/

"The accelerator developed by Kovaleski’s team could be used to create other forms of radiation in addition to X-rays. For example, the invention could replace the radioactive materials, called radioisotopes, used in drilling for oil as well as other industrial and scientific operations. Kovaleski’s invention could replace radioisotopes with a safer source of radiation that could be turned off in case of emergency.

'Our device is perfectly harmless until energized, and even then it causes relatively low exposures to radiation,” said Kovaleski. “We have never really had the ability to design devices around a radioisotope with an on-off switch. The potential for innovation is very exciting.'

The device uses a crystal to produce more than 100,000 volts of electricity from only 10 volts of electrical input with low power consumption. Having such a low need for power could allow the crystal to be fueled by batteries. The crystal, made from a material called lithium niobate, uses the piezoelectric effect to amplify the input voltage. Piezoelectricity is the phenomenon whereby certain materials produce an electric charge when the material is under stress." ... ate+X-Rays

Re: Portable X-Ray Source Invented at MU

Posted: Sat Jan 12, 2013 7:25 pm
by John Futter
Bob I do not know how these people rehash well known techniques into a new discovery story.
We did this at work 10 years ago after some papers were published on the technique. We also concluded that there was not enough energy available from the crystal to make a meaningful number of x-rays to get an x-ray picture of sufficient noise free resolution. From memory I think we got around 120kV @about a micojoule
A few years later i'm sure I saw these crystals discussed here on this board as a high voltage source for a fusor.

In the end we used a cold carbon nanotube electron emitter to make a miniature x-ray tube of multiple millijoule output, no heater, no warmup time and smaller than what was possible with lithium niobate

Re: Portable X-Ray Source Invented at MU

Posted: Mon Jan 14, 2013 6:30 pm
by Doug Coulter
Yeah, I call this "press release science" generated by "publish or perish" types, who don't bother to learn what's gone before them, and don't want to - because if widely known, they might be out of a job, having never actually created anything original whatever. I could list some recent howlers from physorg (and other sources) myself, just laughable stuff.

Recent ones include the "invention of the plasma triode" which you could buy from Phillips in the '50s if you wanted. So, it was invented in 2011? Wow, guy had a time machine. Now that would be news!

Or "red hot tungsten emits green light" after someone had built a "photonic array" that any electrical/RF engineer would immediately see as a phased array of dipoles tuned to green, sucking off the tail of the distribution and radiating it preferentially. Do these light guys not realize that radio waves and light are both photons and follow the same rules, just at different scales?

I could go on, and on, and on, and on....

Re: Portable X-Ray Source Invented at MU

Posted: Mon Jan 14, 2013 9:28 pm
by Carl Willis
In my professional career I work closely with Scott Kovaleski's group on a neutron generator application for the piezoelectric transformer that is referenced in these pieces.

Obviously there is a history of interest in piezoelectric transformers, and neither they, nor the idea of using them as a power supply for vacuum electronics, is new. The UM crew has taken a fresh look at a number of variables like crystal length, resonator shape, output impedance matching and power transfer, measuring the output characteristics (which is not trivial), surface passivation, and drive techniques. On our end, I have investigated methods for implanting deuterium in the surface of the crystal, methods of electroding the crystals, and issues relating to packaging as a neutron generator together with suitable ion sources. I can guarantee that nobody involved is guilty of ignorance or myopia concerning the state of the art.

The author of the IEEE Transactions paper, Brady Gall, is a student at MU. I haven't read that particular paper, but if anyone airs any substantive criticism of the contents in this thread I will bring it to his attention.


Re: Portable X-Ray Source Invented at MU

Posted: Mon Jan 14, 2013 11:43 pm
by Doug Coulter
Glad to hear of an exception to the usual rule, Carl. Stands out as pretty rare, though.
The paper talked merely of X rays, not neutrons, AFAIK.

Re: Portable X-Ray Source Invented at MU

Posted: Tue Jan 15, 2013 12:44 am
by Carl Willis
Doug, I don't know how much of an exception it really is.

Maybe I am going out on a limb here, but I'd say that professional and academic research are largely the domains of well-educated, motivated, and reasonably-competent people! It's probably best to give any of these professionals the benefit of that assumption by default, barring specific and detailed knowledge to the contrary. From time to time this forum's denizens get into a little spirited ITER-bashing...or NIF roasting...or Alcator chops-busting...or indeed UM piezotransformer feces-throwing. Some of that pugnacity is understandable when it targets the ridiculous aspects of doing professional science in a country whose citizens are hostile to funding it and have the sensibilities of fourth-graders. When you see those windy press releases touting "groundbreaking, novel, totally phat" progress, they're written that way to drum up publicity from a population barely entertained by the technology in blockbuster superhero movies yet too soft in the noodle to believe in evolution. To get the real story, you have to dig into the details and get to know the people involved.

Brady's paper does look to be mostly or entirely about x-rays. As I said, I haven't read that one. They have been using x-rays for some time as a method of voltage measurement by looking at the energy spectra with a cadmium telluride detector.