The "depleted" in "depleted uranium" refers to the fact that the percentage of highly radioactive U-235 in it has been reduced from its naturally occurring concentration, leaving a larger fraction of the less-radioactive U-238 that makes up the vast bulk of natural uranium. But depleted doesn't mean eliminated: In fact the radioactivity of depleted uranium is only about 20% less than that of naturally occurring uranium!

That means this cylinder, though depleted, is still the most radioactive thing I have in my collection. It represent about 140 microCuries of total activity (about 300,000,000 disintegrations per minute). A Geiger counter held up to the side of it will read about 100,000 counts per minute. Fortunately, the radiation from uranium and its decay products is mostly in the form of alpha particles that do not penetrate skin. Holding this cylinder is probably not particularly harmful, though it's not something I do for any longer than necessary to shock people. (There is almost certainly a greater health hazard associated with any uranium oxide that might form on the surface and get onto hands and into lungs from there. For that reason I have put a thick coating of varnish over the cylinder. The main sample photograph was taken before I varnished the cylinder, while the 3D version was made after, and clearly shows the thick, glossy varnish.)

100,000CPM is high. That's a contact count rate of course. If you measure the count rate 5 cm away, it would be close to background if it's due to alpha particles.
I'm not sure if I'd want an alpha emitter that hot in my house. If its registering 100,000 CPS through the varnish, it must be picking up some other impurity.

The most radioactive sample I have is around 10,000 CPM.  You can pick similar samples off the road side near a certain disused Uranium mine if you know what you're looking for.

Of course Brazil nuts are pretty good too if you just want something that will register.

John_Taverner wrote on Feb 28^th, 2016 at 5:41pm:



Actually - some objects like bricks can measure well over the normal 40 cpm.
They can be as high as 250 cpm -
so can granite counter tops & crystal glass.
100,000 cpm is ridiculous.

Those Brazil nuts don't look safe to eat.

In the 1950s companies were promoting radioactive toothpaste - laced with a nice dose of Thorium.

In the 1930s Tho-Radia made a whole product line of perfumes, creams, facial powders, lipsticks that contained thorium-chloride and radium.

The Germans in the 1930s manufactured a radioactive chocolate bar called Radium Shokolade. There were even radioactive cigaretts and radioactive woolen garments.

And my favorite - Nutex Radium Condoms

And of course the ladies that were painting the marks on the clocks and watches so that they glowed in the dark. The ladies often used their tongues and lips to make a very pointy tip on their brushes - many died of various cancers - The Radium Girls

I wonder if John knew that Uranium could bind with DNA and cause genetic damage?

There are scientific articles that date back to the 1960s highlighting the direct link between Uranium and damage to the DNA code.

Amazing isnt it John

absolutely amazing

There is ample data and research in the scientific literature that supports the notion that Uranium is chemically genotoxic and mutagenic through the formation of strand breaks in the DNA and covalent Uranium–DNA adducts. Radionuclides such as Sr-90 and Uranium bind to DNA and when they decay cause transmutation ionisation and local electron emission ionisation (Auger, β particle). These localisation and transmutation effects were studied as early as the 1960s. Nobody bothered to introduce these findings into safer work place practices and the use and handling of radionuclides such as Uranium - way too sensitive and too much money to be made.

So the depleted Uranium dumped on Iraq and other places via U-tipped munitions and missiles has serious health consequences - not only for those immediately exposed but for future generations via genetic damage and mutations

Humans are very interesting creatures - very interesting and nuts