Can anyone recommend a reasonably priced Geiger counter to testing older watches for their radioactivity? I mainly want to use it for vintage watches in which I’m uncertain if radium was used.
Thanks in advance!

 

I like the Radex 1212

 

Soeks seem quite popular too. Happy with mine.

 

I am also happy with Soeks.

 

I use a little dongle from FTLAB that I plug into my iPhone.

About $30 and works fine.

https://www.cnx-software.com/2016/0...tion-detector-for-android-or-ios-smartphones/

 

Have you compared it's reading with a dedicated counter?
The reviews on Amazon don't sound promising
https://www.amazon.com/Best-Geiger-..._next_5?reviewerType=all_reviews&pageNumber=5

(Nearly all the positive reviews seem to come from people who have never used a geiger counter; the people who tried calibrating with a known source were mostly dissatisfied)

 

Thank y'all! I've ordered the Radex 1212.

 

I'm not monitoring my continual exposure or conducting experiments to record data, or looking for lost nucular weapons.

Does a watch have radium or not? That's all I need to know.

I put it near a watch with known radium on the dial and it goes nuts.
I put it near a watch with no radium/lume on the dial and it does nothing (except background levels).

That's good enough for me.

 

give us a quick review or thoughts when you test it vs Soeks if you can

 

I should have it in hand tomorrow. I'll share my thoughts after I have a chance to try it out.

 

I agree with the above. I use the same inexpensive iPhone app and it can identify if a watch has radium or not. It is not reliable for accuracy but can answer if the watch is hot or not when I go to open it up.

 

Well I got the Radex RD1212-BT Outdoor edition - obviously so I can take it off roading in a hurricane. Actually it was nominally more expensive than the base model but offered with next day Amazon Prime delivery.



Fired it up and tested it on my suspect dial...nothing. Nothing at all. Well, it did indicate 0.10 background radiation. I suppose that's good but part of me was hoping it would indicate Radium just so I could see it work.





But this poses a question for me - this particular device only detects Beta, Gamma, and X-Ray. NOT Alpha. I'm no nuclear scientist so here comes my dumb question: do I need a geiger counter that detects Alpha particles to determine if I have a Radium dial?

 

You're fine.
Radium emits gamma.
Tritium emits beta.

 

I hadn’t seen the outdoor edition. Everyone is doing limited editions

 

Radium 226 emits alpha.
Several of its decay products emit beta.
A couple of its short-lived isotopes emit beta.
Nothing in the decay chain emits gamma.

 

So are you saying the Radex 1212 will not detect radium lume?

 

Radium and its isotopes emit alpha, beta and gamma rays but the penetrating effects of decayed gamma radiation is the central concern of the OPs watch (and others). Your geiger counter detects gamma and beta radiation NOT the less harmful (though not harmless) alpha rays

 

^^OK, there are maybe forty different isotopes of Radium and a very few go through "Isomeric Decay" that may emit a high-energy photon (gamma emission) but these isotopes have half lives in the milliseconds. You ain't gonna find many of them.

Alpha particles can't get through the layer of dead skin we all wear. I really doubt it can get through the case of that detector.

OP, why don't you PM it to me. I have some old watches and aircraft instruments that are guaranteed to contain radium. Can't say I need one bad enough to spend a couple hundred on it tho...

The reason I mentioned radium 226 is that's the isotope in the decay chain for U238, the most abundant form of Uranium. That's where most of the radium in the crust came from. Interesting, the half-life of U238 is 4.5GY. But it's had plenty of time to decay.

 

I take your point but for this price you are not going to get a picogram-level precision instrument that accounts for long and short half-life isotopes, uranium and thorium minerals etc.

 

It looks like the Waltham dial is lighting up under a UV light. To me, the lume is from tritium which will quickly fade when then UV withdrawn. None of my radium watches light up to UV.