[Milsurplus] Re: [ARC5] Hot meters.. more

[Peter Gottlieb]

I use a PDR-27 which has a mica window GM tube.  It easily picks up alpha 
emitters such as radium.  I have an old altimeter which it can pick up from 
several feet.  This altimeter, now retired from aircraft service, serves as 
my quick go/no-go test source.


----- Original Message ----- 
From: "Scott Johnson" <scottjohnson1 at cox.net>
To: "Todd, KA1KAQ" <ka1kaq at gmail.com>; "Mike Hanz" <AAF-Radio-1 at cox.net>
Cc: "ARC-5" <arc5 at mailman.qth.net>; "Gordon White" <gewhite at crosslink.net>; 
"Milsurplus" <milsurplus at mailman.qth.net>
Sent: Wednesday, May 04, 2005 2:31 PM
Subject: Re: [Milsurplus] Re: [ARC5] Hot meters.. more


> Here's what I know (in general) about dial face paint:
>
> 1.  White- non-phosphorescent,designed for flood lighting in vehicles or 
> aircraft
>
> 2. Green(ish) phosphorescent, needs UV stimulation to glow NOT 
> Radioactive. This was used in earlier WWII aircraft and Link trainers with 
> flourescent black lights.
>
> 3. yellowish-brownish- could be self-luminescent, radium or other alpha 
> emitting isotope mixed with a phosphor (best checked with a scintillation 
> counter that is capable of detecting alpha emission.  Alpha particles can 
> be blocked with paper, so most geiger counters are rather insensitive to 
> them. This paint is dangerous if ingested, but I believe it was 
> discontinued by around 1944.  This paint should no be confused with plain 
> yellowed paint that is often seen on aircraft istruments that have sat in 
> the sun for years.
>
> 4. Sealed tritium ampules with a phosphor coating on the inside of the 
> ampule-  This is used in newer compasses etc, and is much safer than the 
> radium paint, because the tritium gas is sealed in the ampule, and even if 
> broken, it disperses rapidly, leaving no radioactivity behind.
>
> Probably the most potentially dangerous sustance is the radioactive paint 
> applied to knobs and engraved legends on early WWII radios, it tends to 
> flake off, and if ingested, is quite capable of lodging in the lung and 
> starting a little tumor party.  I stay away from that stuff, and I am not 
> exactly known as Mr. caution!
>
> If anyone has serous concerns about the presence of radioactive paints, I 
> will loan them my scintillation counter for the price of two-way shipping 
> (or  pick up in the Phoenix area)  BTW, I have yet to find an R-390 or 
> GRC-106 meter that was radioactive, all I have seen are phosphorescent.
>
> Scott
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