Vintage radioactive wrist watches - Is Radium really nasty?

[jebem]

(01-18-2015 01:44 PM)Thomas Klemm Wrote:  

(01-18-2015 11:19 AM)jebem Wrote:  Considering the current safety standards, what would be the risk level for someone using that watch for a full year, accepting the monitored value of 39uSv/h?

That would be about 340 mSv per year. Compare this to:

Quote:Maximum yearly dose permitted for US radiation workers (50 mSv).

Thanks, Thomas!
It is better to be safe than sorry. I have to put these two watch hands away in the cellar. Just in case!

(01-18-2015 02:28 PM)walter b Wrote:  

(01-18-2015 01:44 PM)Thomas Klemm Wrote:  ... about 340 mSv per year. Compare this to:

Lowest one-year dose clearly linked to increased cancer risk = 100 mSv.

Clearly these radioactive compound products should be banned from the market for safety reasons. The true is that I bought these vintage watch hands from the eBay, legally, about two years ago.

I believe I took the minimum safety precautions handling it. I never opened the hands plastic bag container, and this package is going to a safer place away from me in my garage/cellar for the next 1600 years
Is that the Radium half-life I'm reading in Google? Really? How come we mortals spend at most 100 years on earth and a tiny heavy atom in excess of neutrons lives as much as 16 times more only to lose half of its material? Not fair!

And thank you for the excellent explanation on the Radium disintegration!

It reminds me of my professor Campos at Maputo University Physics Department (Mozambique) when he spent time to explain me the mysteries of Universe at a coffee table after school. He used to drive a nice 60's Porsche, I think it was the Speedster.
He used to express some extravagant ideas at the time, and some of them came true today.

(01-18-2015 05:40 PM)Katie Wasserman Wrote:  

(01-18-2015 11:19 AM)jebem Wrote:  I have built my own high voltage DC-DC converter circuit consuming only about 4 mA under load.

I've made some tiny little GM tube detectors/counters too and did a little better on my home made high voltage supply specs (under 100 ua at 6 volts input). However that's still not good enough for me.

I prefer to use the LND-712 tube as it has a mica window to allow in alpha particles, but it's much more expensive (and fragile) than the Russian tubes.

For the power supply I've been using these, tiny, incredibly efficient modules:

http://www.ebay.com/itm/Geiger-counter-p...257eaa7ce3

Which will power the tube for over a year on a single CR2032.

Thank you so much for your extra information, Katie!

Yes, I have been looking to build something to detect Alfa particles as well, and the LND-712 with mica ending seems to be a good candidate.

Now, that HV power supply is amazing!
Expensive, but it looks really efficient!