And here we go again, this time in Thailand.
There’s also an orphan source (that’s the name for these things) loose in Houston, Texas since March 9:
This sort of thing is more common than most people thing, and certainly more common than anyone would want.
And more …
Two and a half tonnes of uranium have gone missing from a site in Libya, the UN’s nuclear watchdog has said.
Knowing the Libyans they probably got conned by an inventor and swapped it for a bunch of pinball machine parts.
There is a BIG difference between 2-1/2 tonnes of uranium and 2-1/2 tonnes of uranium ore. And the badly-written article is actually talking about 2-1/2 tonnes of uranium “yellowcake”. Which is an intermediate form of semi-refined product.
Still and all, somebody was willing to move ~5,500lbs or ~2500kg of dense sand-like substance to get this stuff.
Speaking of Cesium-137…
Marie was pretty careful with her materials, and so it probably was the gamma radiation that caused her health problems, but the “radium girls” in the watch factory were actually ingesting small amounts of radium, and for ingested material, alpha is much more dangerous than gamma.
No one in those factories realized how dangerous it was. Curie herself was incensed when she found out about the case, because she did know the dangers, and how bad their procedures were.
Yes, the girls used their mouths to make a fine point on the brushes they used. The outcome was horrific.
Radium and Americium effectively both emit gamma rays.
Americium 241 emits a characteristic 59kev gamma ray and as such americium sources can be embedded in spectral gamma ray detectors as a low point calibration point.
Technically it’s one of the metastable states of one of the daughter products decaying that kicks out the gamma ray, but given the relative half lives it’s a moot point , americium emits gamma rays.
When talking about how dangerous a radioactive isotopes is becomes very tricky and saying one thing is more harmful than another based on the isotope alone is not helpful.
You have to consider the source as a whole ,
How active the source is ( disintegrations per second measured in bequerelle or curies)
What the products are including daughter products in terms of energy AND type ( alpha beta gamma X-ray neutron ) Different products have different quality factor which relates to how much harm that do to organic material. Gamma ray QF is 1 , fast neutrons are 20 if I recall correctly. Plus for daughter products .
Then you have to consider where the source is, it it is external to a person, the the alpha and beta energy is less of an issue and gamm xray and neutrons will be the main things contributing to absorbed dose.
If it is inside you, then alpha particles are a big issue , high energy and high QF and all being absorbed by the body. The gamma rays may be way less of an issues ( low QF low energy) and some will pass straight out the body. The alpha particle energy is being entirely absorbed by the body. Which is not ideal.
Yeah, gamma sources are about equally dangerous no matter what you do: On the surface of your skin, inside your lungs, in a safe on the desk next to you, whatever (the safe would technically be less bad, but only slightly, because to a gamma ray, that’s only a trivial amount of shielding). Beta sources are only slightly dangerous outside of the body, and alpha sources basically not at all, but both become extremely dangerous inside of the body.
Great find. Thank you.
What’s interesting to me is the Texas Department of Public Safety AKA state police and investigative agency, has a whole division devoted to radioactive threat detection and some dude was driving around the state with radiation detectors in his car when they went off. And that’s how they found the source.
How many people are the taxpayers paying for to drive around the state waiting for a rad detector to trigger? And why? Their website is uninformative on this.
Luckily, blue latex gloves make it safe to handle.
I wondered about that too. Obviously duration of exposure matters.
Cs-137 has a half life of ~30 years and mostly decays directly to non-radioactive stuff. A slug made in 1967 is now ~60 years old, so should now be putting out about about 1/4th of the original radioactivity level. Whatever that was.
Cs-137 seems to be a beta emitter with an immediate daughter that’s a prompt gamma emitter.
IANA expert but I think I’ll pass on playing catch with it, blue gloves or no.
100 millicuries. 25 still seems spicy.
The amount of shielding against gamma rays for any given material type and thickness is heavily dependent on the gamma ray energy and the source activity.
For higher energy gamma ray ( approx >300 kev) Gamma rays shielding is really about how many electrons can you get between the source and the target. The more electrons the more probability a gamma ray will be absorbed. Electron density scales with mass density ( yeah hydrogen is a complication for density measurements) . So a dense material and a thicker material will clearly absorb more gamma rays.
For lower energy gamma rays the number of electrons between source and target is important but the nucleus takes a larger role, beryllium has a perfectly large capture cross section for low energy gamma rays , and so material type can have an impact for lower energy GRs
A source such as the fluid density measurement source found in Texas would be likely just fine in a safe ( well you would be likely just fine ) as it’s fairly low activity. One of the sources that kicked off this discussion I believe are 1-2 curies so pretty spicy , that would be better off in a larger container. That said the 2Ci logging sources we used in oil well logging would be stored in something the size of a 20lb propane cylinder and could be handled by two people and we’re ok to have arround non dosimeter badged people .
Correct ca137 goes to Ba137m which has a half life I think of a minute maybe . That kicks out a 662kev Gamma ray , although that decay path is only about 85% of the time ( running on memory there)
If one wanted to you could assume half the energy is going into the hand so 0.25 milli Ci x 662 kev . So cenvert the curies to Bq ( disintegrations per second) divide by half. Then multiply that number by 662 kev and convert to joules. Quality factor of 1 for GR so we don’t need to mess with that. That would give you the energy absorbed .
Now as it’s 662 kev gr , you may actually find that some gr go straight through the hand, and oddly a higher energy source even more GR would go through the hand , but each one that was absorbed would dump more energy so it balances out .
No, those are mostly for shielding against \psi radiation.
And, aside from the sectional density, precisely what the material is doesn’t matter much. So in practice, gamma shielding is usually just earth or concrete or whatever you can cheaply get several meters’ thickness of.
Yes get as many electrons between you and the source how best you can , if you don’t have a lot of space steel or lead is good. As I mentioned above material type is a factor for lower energy gamma rays, although that’s more specialist shielding needs. You would use a lot of lead arround a density gamma ray detector , but then have a thinner layer or cadmium to shield from the lead x rays produced by cosmic rays hitting the lead shielding .
Regarding the gloves I’d imagine that’s just a thing they do when handling anything. It’s unlikely any alpha or beta particles are getting out of the sealed source housing, and step one on finding the source would be to wipe test it for potential leaks. That basically involves rubbing it with some alcohol and paper and checking that .
Not true.
It came out during the Radium Girls trial against the United States Radium Corporation (USRC) that the men formulating the paint, that is, mixing it from raw materials, wore protective gear and were very careful not to get it on them. They knew how hazardous it was. The company’s chemists had lead screens, tongs, and masks. USRC had distributed information on the injurious effects of radium to medical people in the industry. They knew.
The young women were seen as disposable. When they got sick then died the company blamed it on syphilis, basically accusing the young women of being whores. They blamed it on the diagnostic x-rays used to investigate and document the illnesses of the young women. When the women workers fell ill the company referred them to people who weren’t actually doctors who were cooperative with the company’s attempt to hide the evidence. USRC did absolutely everything to avoid blame and hide the fall out of their shoddy practices.
Not that the men were entirely immune - the inventor of the radium paint and USRC’s chief chemist both died from radium poisoning as well. Funny, though - no one accused them of having an STD…
Yes.
It was excused as “national security” or some such. But with more protection for workers. Still not convinced it was enough, presumably others felt the same, hence the eventual ban.