[R-390] meter luminescence

[Adam Vaughn]

> The Victoreen CDV-700 Geiger Counter *must* be detecting secondary byproducts.
> 
> Radium is an alpha particle emitter.  Alpha particles will not even penetrate paper or unbroken skin.
> 
> The only way to detect alpha particles with such a device would mean that the meter has been opened and exposed to the surroundings.
> 
> Additionally, the CD versions of counters are very coarse and only read in high ranges.
> 
> It would require something such as an Eberline 500 to get accurate readings.
> 
> Bob - N0DGN

Yeah, I should have clarified that when I got the 'hot' reading, I had the "beta shield" on the CDV-700's probe open, and the meter was pegged on the meter's most sensitive range (though at times, trying the next setting up showed some meter deflection). With the beta shield closed, the count was far lower, naturally, though I did get some deflection. I wasn't going for an accurate reading, just to see what reaction I got, and get a reaction I did! I also get a 'hot' reading from my Jefferson "Golden Hour" 'mystery clock' from the 1950s, as seen here:

http://www.roger-russell.com/jeffers/jefhour.htm

Unlike the R-39x meters, there's no glass cover to shield the radiation, so that could explain the high readings. Still makes me nervous every time I have to put my fingers near the hands to set the clock...
-Adam

--
Adam Vaughn
Collector of old computers, video game systems, radios and other electronic
equipment...
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