So, ISIS may have/get Iridium 192

According to the UK Independent

Iraq is searching for “highly dangerous” radioactive material stolen last year amid fears it could have fallen the hands of Isis jihadis.

The material, stored in a protective case the size of a laptop, went missing from a US-owned storage facility in Basra last November ber, according to leaked environment ministry documents.

An unnamed senior security official with knowledge of the theft said: "We are afraid the radioactive element will fall into the hands of Daesh (Isis).

According to the comically named Iraq “Centre for Prevention of Radiation” the “device”
“… contained up to 10 grams (0.35 ounces) of Ir-192 ‘capsules’, a radioactive isotope of iridium also used to treat cancer.”


  1. That “device”–is that the “protective case” mentioned in the first paragraph?

  2. Leaving aside the “device”…that amount of Ir-192: is 10 grams a large or small amount for medical work? For nuclear “research?” For irradiating…what danger to people/property in conventional-explosive dirty bomb scenarios, or in plain old, here-hold-this terms?

  3. Those “capsules”: how much do they contain–I’m thinking if they’re already each nice and safe packages, distribution of smaller amounts of the whole haul is that much easier.

What do those capsules look like? Presumably they attenuate the radiation–by how much (i.e., how easy to set off buzzers)?

Ir-192 mostly emits beta and gamma. The beta isn’t too hard to block, but the gamma is very difficult. It has a half-life of a few months, which is both good news and bad news: On the good news side, it won’t take long before it’s harmless, but on the bad side, such a short half-life means that until it does decay away, it’s especially active.

Not bad for the JV team, we need not worry about.

Was that meant to go in a different thread? Because it doesn’t seem to make much sense here.

davida03801 never misses a chance to bring up his anti-Obamaness.

It seems the President didn’t show up for his shift on guard duty in Basra.

It could be a radioactive source projector like this, used for industrial radiography (i.e. taking “X-ray” pictures of metal structures, except it’s using gamma rays instead of X-rays). Here are diagrams; basically, it’s just a lot of shielding material, and a remote mechanism that moves the radioactive isotope out of the shielded box.

I’m not sure what they mean by 10 grams. The amount of radioactive material is measured in activity (Curie or Becquerel). I don’t think it means 10 grams of pure Ir-192, I think that would be way more than you ever see in one place (though I don’t have a feel for these numbers, all the radioactive material I ever work with are no more than a few milligrams.)

Wiki. Looks like a few pictures of what I presume is pure iridium.

It’s going to be easy to spot, provided you’re looking with a radiation detector. (And why it, and other industrial gamma sources like it, are kept in a heavily shielded case.) Thankfully, most ports and large cities in the West have multiple radiation detectors to find crap like this before it does too much damage out in the wild. See, for example, this Wired magazine article on an Italian freight container that, for some reason, showed up in Genoa emitting insane amounts of radioactivity.

If you don’t spot it quickly, OTOH, you end up with catastrophes like Goiania and Juarez.

Playing around with a rad safety online calculator here, I get, from a point source of 10 grams of Iridium-192, with a stated specific activity of 550-600 curies per gram, at 10 feet away, a radiation dose per hour of 305 Roentgens per hour.

Or around 2 and 2/3 Sieverts per hour. Just from the gamma. Whoever’s close to that source is rapidly going to have a bad time.

Edit: Reading scr4’s post, silly me thought that when the news said 10 grams, they meant it was pure. Yeah, I don’t know what activity this particular industrial source is going to have, and how much it’s diluted. Play around with that linked calculator and see if it makes things any better. My take is that the guys in ISIS stand a decent chance of kiling themselves with it, before they can weaponize it as something that’ll achieve their terror goals against the West.

Yes, but that isn’t Ir-192. That’s plain old Ir-193. Or Ir-191. Either way, stable.

Actually, based on that number, 10 grams may not be so farfetched. This supplier seems to sell Ir-192 capsules up to 3000 Ci, which is about 5 grams of pure Ir-192.

Well, that was my question (ultimately a tautological one): how shielded is shielded, vis a vis different levels of use: a gun in a travel bag is shielded from visual sight, not other radiation imagery. The “travelling cases” for these products: presumably they can be schlepped safely (briefly?) by an unshielded person (right?). But you say more rigorous methods spot them, so that’s good.

The calculator I linked to also as a module for calculating required shielding thicknesses to reduce the radiation flux from X to some desired 1/X^n. For the 305 R/hr sources I mentioned in my post, you need 6 inches of lead to knock that down to 1 microR/hour. About 3.5 inches of lead to 1 milliR/hr. The cases for these sources aren’t small—here’s a company that sells a Ir-192 source like the one mentioned in the article. Photo of source.

As to how do you detect these? Well, you can detect the primary radiation flux from the source, and proper shielding should attenuate that. I don’t know how radiation detectors used for screening for radioactive weapons work: whether they look for certain wavelengths of gamma radiation that most likely only come from weaponizable isotopes and their rarer daughter isotopes, whether they look for more exotic radiation (neutrons, muons, and the like) that are tougher to attenuate than gamma radiation, whether they look for secondary radiation that arises as a result of the flux from the primary radioactive source. Neutron radiation—like you’d have from fissionable material like Pu-239 or U-235—is supposed to be even tougher to keep away from a detector. Which is good. Whatever they look for, detection is going to come down to distance, signal and noise.

However, if the material in the final weapon is properly shielded to avoid all of that, it’s going to be a lot tougher to do that, and still keep the radioactive material in a container on the order of the size of the sources I linked above. Make the final weapon on the order of something a dump truck could carry though? That seems possible.

I agree with you, but would Ir-192 look any different than any other isotope of Iridium? Do different isotopes of the same element, provided they aren’t glowing red hot from decay heat, or small enough to have drastically different physical properties than the most common isotope, look any different?

No, they don’t look any different except in very rare circumstances. Just sitting on a table? No, no visible difference.

Even if it was pure when it was stolen, its already been missing for two half-lives, so there probably isn’t much more than two grams left. And its main daughter elements are stable. So if someone wants to build a dirty bomb out of it, they’d best get a move-on.

Practically speaking…the danger of a dirty bomb is it to be radioactive enough that when it is blown up the feds run around in paper suits and booties with gieger counters and the general population freaks the hell out…but the actual cancer deaths are undectable.

Not to say that ISIS/whoever CAN"T get some seriously dangerous shit…but IMO this ain’t it.

Not only do ports scan for radiation, they also scan for radiation shielding. This is primarily done by measuring naturally-occurring cosmic rays. Of course, shielding material can be innocuous (enough thickness of anything at all will make a good shield), but if you’ve got more shielding than your shipping manifest would imply, then you’ve got some explaining to do.

I was thinking more along the lines of “amount.” The missing iridium won’t look like the photo. It will likely be pelletized. It will also be largely inert by this point. If you are going to build a dirty bomb, you have to keep in mind the “Best by…” date on your radioactives.

Thank you for these cites. Interesting as hell.

Moderator Note

If this was meant to be a pot shot against Obama, let’s not have any of this sort of politics in GQ.