Spinthariscope

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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Eldarion
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Spinthariscope

Post by Eldarion » Thu Dec 17, 2009 4:43 am

Just wondering, is there any possibility to not use these to detect proton recoil from alphas, but to detect protons from D+D=p+T fusion reactions? If so, it would make a good poor boy neutron detector.

Dustinit
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Re: Spinthariscope

Post by Dustinit » Thu Dec 17, 2009 6:58 am

It will also glow when exposed to ultraviolet, xrays or electrons. How would you differentiate. (http://education.jlab.org/itselemental/ele030.html)


I've also often wondered if you would get bubble neucleation from neutrons in water heated from the top down.
Like a cup of water in a microwave, you put the coffee in and it boils over because the surface water >100C but cant neucleate to boil because water below is <100c.
This would make the surface supercritical allowing neutron bubble neucleation.
Interesting theory but I have no means to test it.
It occured to me from ultrasonic cavitation bubble fusion (teleyarkin? et al) used neutrons to neucleate bubbles in deuterated acetone.

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Doug Coulter
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Re: Spinthariscope

Post by Doug Coulter » Thu Dec 17, 2009 2:47 pm

This is essentially what a Hornyak button is -- some H containing material (plastic, epoxy) and some phosphor. In my personal experience, the phosphor-naked eye combo just isn't good enough for this work. I never really saw flashes from a spinthariscope even dark adapted and sitting on a smoke detector that made my geiger counter go pretty good. Now, my night vision isn't the best, but IIRC even Rutherford needed optics and willing helpers using good tricks to get his data counted.

A phototube sure is more convenient, despite some propensity to also pick up electrical noises on the way to the preamp if you're not careful about such things.
Why guess when you can know? Measure!

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Richard Hull
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Re: Spinthariscope

Post by Richard Hull » Thu Dec 24, 2009 4:48 pm

My eyes are ancient and take a full 10+ minutes to dark adapt, but my several homemade Spinthariscopes all flash nicely to my eyes. Most of mine are Ra based, but that is not important. Just having a good alpha source is important, coupled with a good ZnS:Ag screen.

Generally, the source needs to be within a cm or less of the screen. Ultra hot sources are to be shunned, for the most part. A uniform glow will result from too hot a source.

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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Doug Coulter
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Re: Spinthariscope

Post by Doug Coulter » Thu Dec 24, 2009 5:22 pm

That may have been my problem, Richard. I bet my source was too hot for this.
Why guess when you can know? Measure!

Jon Rosenstiel
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Re: Spinthariscope

Post by Jon Rosenstiel » Thu Dec 24, 2009 5:48 pm

To mellow out your smoke detector source spray on a thin coat or two of paint or clear lacquer.

Jon R

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