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Jim Koepke
06-08-2018, 2:00 PM
This would be on cameras made between the 1940s and 1970s.

It comes from using thorium dioxide in lenses to improve performance.

https://petapixel.com/2018/06/07/a-radioactive-lens/

Low level exposure but likely not enough to get rich on a law suit.

jtk

Malcolm Schweizer
06-08-2018, 4:42 PM
Wow- I had a Leica 50mm Summicron. I wonder if the Summilux also had this glass. I never knew about this- I’ve owned many Leica cameras and lenses, early and late vintage.

Doug Dawson
06-08-2018, 4:59 PM
This would be on cameras made between the 1940s and 1970s.

It comes from using thorium dioxide in lenses to improve performance.

https://petapixel.com/2018/06/07/a-radioactive-lens/

Low level exposure but likely not enough to get rich on a law suit.

Alpha emitter, not really harmful unless you eat it. Doesn't penetrate the skin, but perhaps useful as a teachable moment to instruct your teenagers Plutonium cores for nuclear weapons are analogous emitters, which is why they're nickel-plated and you can hold them in your hand (slightly warm to the touch though.)

Ole Anderson
06-08-2018, 9:03 PM
Alpha emitter, not really harmful unless you eat it. Doesn't penetrate the skin, but perhaps useful as a teachable moment to instruct your teenagers Plutonium cores for nuclear weapons are analogous emitters, which is why they're nickel-plated and you can hold them in your hand (slightly warm to the touch though.) Whaaaaat??? Seriously?

Frederick Skelly
06-08-2018, 9:40 PM
How about radium dial wrist watches? They are radioactive too.

Mike Cutler
06-08-2018, 9:54 PM
\ Plutonium cores for nuclear weapons are analogous emitters, which is why they're nickel-plated and you can hold them in your hand (slightly warm to the touch though.)

Spent a few years playing with nuclear weapons. The actual physics package was in fact not very large, but large enough that you'd need at least both hands.
You'd still get dose from holding them. I got enough dose from just handling them as REB's, completely intact. ;)

More than a few products made in the 40's-60's would be classified as nuclear materials/nuclear waste these days. I see them in antique stores and flea markets. As long as you don't hold a frisker up to them, you won't know. The glass in the lenses would have been a very good shield material.

Ole Anderson
06-09-2018, 12:37 AM
There is a story of gals getting radiation poisoning painting the radium on watch dials and hands when they would point the tiny brush bristles with their lips. https://en.wikipedia.org/wiki/Radium_Girls
https://www.npr.org/2014/12/28/373510029/saved-by-a-bad-taste-one-of-the-last-radium-girls-dies-at-107

Lee Schierer
06-09-2018, 9:45 AM
Fiesta dinnerware is also radioactive (https://www.thoughtco.com/how-radioactive-is-fiesta-ware-608648) if it was made between 1936 and 1972.

Michael Weber
06-09-2018, 10:27 AM
Anyone else remember the shoe store appliances where you inserted you feet and looked through a viewer to see the bones in your feet and how the fit of the shoes was? I was told later that occasional exposure to customers wasn't particularly harmful but it affected shoe store employees because of long term exposure. They didn't stay around very long thankfully.

Dave Sheldrake
06-09-2018, 12:43 PM
Red tip Tig tungstens are also radioactive for the same reason Th232, same Mike, it always amazed me how something so physically small could do so much damage.


How about radium dial wrist watches? They are radioactive too.

So are bananas :0 decay of Potassium 40

Doug Dawson
06-09-2018, 1:24 PM
Spent a few years playing with nuclear weapons. The actual physics package was in fact not very large, but large enough that you'd need at least both hands.
You'd still get dose from holding them. I got enough dose from just handling them as REB's, completely intact. ;)


As I recall, most of the (pre-splodey) radiation from a (typical) thermonuclear weapon originates from the uranium thermonuclear fuel, from which it's impossible to _completely_ eliminate short-half-life contaminants. (Not the plutonium cores, which are delightful little hollow grapefruits.)

On the subject of handling radioactive material which does relate to woodworking, it's been reported that it is _not_unusual_ for the mainland Chinese to have used contaminated metal in their castings, resulting in hot machine tools. It's worth checking them with your Geiger counter, if you're interested in such things.

Jerome Stanek
06-09-2018, 4:19 PM
Anyone else remember the shoe store appliances where you inserted you feet and looked through a viewer to see the bones in your feet and how the fit of the shoes was? I was told later that occasional exposure to customers wasn't particularly harmful but it affected shoe store employees because of long term exposure. They didn't stay around very long thankfully.

I had my shoes fit that way when I was younger

Bruce Wrenn
06-09-2018, 10:01 PM
I have a set of green Pyrex glass mixing bowls that came from parents. When exposed to a "black light", they glow indicating that they are radioactive. This is the most common test used by collectors to make sure they are "genuine," and not fakes. Go in an antique store and if you someone shining a flash light (black light) on green glass items, this is what they are doing

Mike Cutler
06-10-2018, 7:31 AM
Doug
You removed the "retired nuclear physicist" from your original posts? That's pretty cool, you should have left it.
Are the Chinese reprocessing radioactive materials?, or is the ore contaminated?

I don't think we can keep going on the first subject. ;)





Bruce

"Radioactive", or irradiated?
Using point sources, the colors of glass, some minerals, and semi precious stones can be altered, thus changing the original color. For semi precious stones, this can make them worth much more than they should be.
I knew about the high lead content in pyrex. Didn't know about the glowing. That's pretty interesting.

Doug Dawson
06-10-2018, 9:31 AM
Doug
You removed the "retired nuclear physicist" from your original posts? That's pretty cool, you should have left it.
Are the Chinese reprocessing radioactive materials?, or is the ore contaminated?

I don't think we can keep going on the first subject. ;)


All of what I posted is public information, I wasn't giving anything inside, don't want to create that impression even casually.

Ob the metal contamination, I would be really surprised if that hadn't been discussed in this forum before? It was a big deal a few years ago with the Golania incident.

You could look at https://en.wikipedia.org/wiki/Radioactive_scrap_metal
as well as https://en.wikipedia.org/wiki/Goi‚nia_accident for the Golania thing.

Also https://www.seattletimes.com/nation-world/the-growing-global-threat-of-radioactive-scrap-metal/

It's easier to catch hot tools at the ports of entry these days because of radiation monitoring, until you consider that those are mostly spot-checks. Of perhaps greater concern are older Chinese imports, from a time when it seemed that they were less ethical about what they would melt down than they are now. http://theweek.com/articles/498611/made-china-seven-toxic-imports

John Sanford
06-11-2018, 8:35 PM
Fiesta dinnerware is also radioactive (https://www.thoughtco.com/how-radioactive-is-fiesta-ware-608648) if it was made between 1936 and 1972.

I love this, from the article:

There is no evidence that the people who made these dishes suffered any ill effects from exposure to the glazes, so you probably don't have a lot to worry about by just being around the dishes.

Now, keep in mind, these are the folks who were exposed to the glazes daily, sometimes for years, while the glazes are NOT cured/fired, i.e. they are not bound mechanically, so there would be lots of free floating dust from the glazes, glazes on fingers, etc.

Reading the rest of the article, it sounds like you should simply display the Fiesta Ware behind leaded glass, if you even dare to keep it in the house. The reality is, "so what?" A collector of such is more likely to die from a stress/startle induced heart attack due to dropping a piece than they are from any increased cancer risk.

Mike Cutler
06-11-2018, 9:27 PM
John

Wow!! U238 ore. Unbelievable! :eek:
I have worked in the nuclear field since I was 19. First in the nuclear weapons area, and then commercial nuclear power.
If those cups are as radioactive as they state, they're not something I would want in and around my house. We go nuts at work keeping people below the background levels of those cups.
I never knew this.

Dave Sheldrake
06-12-2018, 8:20 AM
I have a set of green Pyrex glass mixing bowls that came from parents. When exposed to a "black light", they glow indicating that they are radioactive. This is the most common test used by collectors to make sure they are "genuine," and not fakes. Go in an antique store and if you someone shining a flash light (black light) on green glass items, this is what they are doing

It's Vaseline glass that's radioactive Bruce

Dave Sheldrake
06-12-2018, 8:28 AM
If those cups are as radioactive as they state, they're not something I would want in and around my house. We go nuts at work keeping people below the background levels of those cups.

At the posted levels they would set off the gate screamers and cause the HP's to have heart attacks at Aldermaston :)

Peter Kelly
06-12-2018, 9:39 AM
https://i.imgur.com/uxc9sTT.jpg

1953, just across the Strip from where the Wynn is now.

William Adams
06-12-2018, 10:17 AM
The problem here is keeping folks honest about what the dosages are, and of course the cumulative effects:

https://xkcd.com/radiation/

Frederick Skelly
06-12-2018, 8:44 PM
1953, just across the Strip from where the Wynn is now.

Sure hope the prevailing winds were blowing the other way!