X-Ray shield your Hornyak Button?

This area is for discussions involving any fusion related radiation metrology issues. Neutrons are the key signature of fusion, but other radiations are of interest to the amateur fusioneer as well.
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George Dowell
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X-Ray shield your Hornyak Button?

Post by George Dowell » Wed Sep 28, 2011 6:04 pm

See the patent .pdf.

This German company states "It has long been known".......... that a layer of ZnS(Ag applied to and around a scintillation
crystal will boost the low energy gamma detection capability, down to <30 keV to about 15 keV.

This was a recent topic on the Spectrometry board where we discussed the possible reasons for this statement, is it true, and what's going on.

Conventional wisdom on the US side of the pond is that ZnS(Ag) while being the penultimate alpha detector, rejects gamma rays period.

Yet the German information persists.

To put an end to it one way or the other, a listmember did an X-Ray analysis of one of our GEOelectronics ZnS(Ag) Alpha Scintillator screens.

The results were astonishing and totally unexpected. Under a weak X-Ray beam ( only 10 microAmps), the ZNS(Ag) lit up with a blue glow, easily seen by the naked eyes. Form 15 to 50 keV,(instrument limit) it just go brighter and brighter. See .jpg's. The black background one is as taken with a not too sensitive Nikon CCD camera, no intensifier at all. The Blue background was digitally enhanced. To the naked eye, the blue glow was very evident.

A microfocus X-Ray beam is used, the actual spot is abiut 3/8".

Test Everything.


Geo
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Doug Coulter
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Re: X-Ray shield your Hornyak Button?

Post by Doug Coulter » Thu Sep 29, 2011 6:52 pm

I check Geo 100% on all this. While my Hornyak works fine when placed behind the shielding on my fusor, it goes nuts with X rays if I put it over the (deliberate) hole in my lead shield. I added a .040" thick lead cap for the button and the phototube, and now it's a lot happier for general work.

More here:
http://www.coultersmithing.com/forums/v ... f=11&t=440
Why guess when you can know? Measure!

AFW
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Re: X-Ray shield your Hornyak Button?

Post by AFW » Wed Oct 26, 2011 10:08 pm

The original "optical" detector for X- rays was barium platinocyanide, or, as it would now be known, barium hexacyanoplatinate. I don't know what range of wavelengths it covered.

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Doug Coulter
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Re: X-Ray shield your Hornyak Button?

Post by Doug Coulter » Thu Oct 27, 2011 8:43 pm

Wiki doesn't have much on this. Here's one article that mentions ZnS as a better phosphor in early work.
http://en.wikipedia.org/wiki/Friedrich_Oskar_Giesel
(who died of too much radiation, by the way)

ZnS certainly more affordable, even though it's not cheap either. The short-blue of ZnS:Ag matches most bi-alkali phototubes sensitivity peak quite nicely. Eljen sells it in the right form for using in our work, for about $150 per 50 grams the last time I bought some. I think United Nuclear sells it too. Since it's pretty dense, that 50 grams isn't a lot.
Why guess when you can know? Measure!

jcs78227
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Re: X-Ray shield your Hornyak Button?

Post by jcs78227 » Fri Oct 28, 2011 12:27 am

Anthony Webb wrote:
> The original "optical" detector for X- rays was barium platinocyanide, or, as it would now be known, barium hexacyanoplatinate. I don't know what range of wavelengths it covered.

Correction: It is now know as barium tetracyanoplatinate(II), BaPt(CN)4. The tetrahydrate, BaPt(CN)4 • 4H2O, is employed when constructing X-ray screens or other items that respond to ultraviolet and X-ray photons or cathode rays.

-Jonathan

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Richard Hull
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Re: X-Ray shield your Hornyak Button?

Post by Richard Hull » Fri Oct 28, 2011 1:31 pm

Chemists are always renaming things to conform to the modus du jour. Try and look stuff up in a CRC using any sort of normalized or common chemical name, especially the organics. Gee I was just gettin' used to luna caustic, sal soda and blue vitriol.

Oh, you don't even want to try and purchase any Barium Platinocyanide in today's market. ZnS:Ag is costly enough.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
Retired now...Doing only what I want and not what I should...every day is a saturday.

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