Jul 30 2007
Polonium’s Close Radioactive Cousin Americium Found In Ship Graveyards
Here is a bit of disturbing news right that relates to the Litvinenko death by radiation poisoning in November of last year. A close deadly cousin of Po-210, the substance that killed Litvinenko and was found all over London and which poisoned many other people (including two Russian businessmen), is the element Americium-241 (Am-241). It has the same general properties as Po-210 in that it is an active alpha emmitter (see here for Am-241 and here for Po-210). It also shares radioactive features with uranium since it is also a gamma emitter.
Why am I telling everyone this? It seems lots and lots of Americium can be found in cruise ship graveyards:
In what is bound to cause another twist to the ill-fated story of ‘Blue Lady’, currently anchored 4,000 feet off Alang coast, Tom Haugen, the erstwhile project manager of the ship (then called ‘SS Norway’), wrote to the Committee of Technical Experts set up by the Supreme Court, claiming that the ship has radioactive material  Americium 241  on board in at least 5,500 fire detection points.
The SS Norway was once the pride of the French fleet. Now it is a treasure trove of radioactive material which is very deadly and would make a good basis for a nuclear dirty bomb.
But this begs the question: since Americium is so much like Po-210 as an alpha emitter, and only a millionth of a gram of Po-210 (for Am-241, easily found in a few fire detector sensors) was required to kill Litvinenko, why didn’t the so called Russian assassins use this material to kill Litvinenko in London? It would not be traceable to Russia and could be acquired in the UK, no doubt.
It would seem we have another example of why there is little evidence the Litvinenko death was an assassination versus a smuggling effort gone bad. In fact, there is more and more indication that the smuggling effort gone bad makes sense. For assassination, Am-241 would have been cheaper and stealthier, less traceable to Russia and easier to obtain. But somehow these sophisticated killers went for Po-210 instead? Riiighht!
There’s no doubt that Americium is readily available. It’s in virtually every smoke detector made . . . the radiation source in an ionization chamber detector is a very small disc, about 3 to 5 millimeters in diameter, weighing about 0.5 gram. It is a composite of americium-241 in a gold matrix. The average activity in a smoke detector source is about one microcurie, 1 millionth of a curie.
Americium emits alpha particles and low energy gamma rays. It has a half-life of about 432 years. The long half-life means that americium decays very slowly, emitting very little radiation. At the end of the 10 year useful life of the smoke detector, it retains essentially all its original activity.
Maybe they didn’t like the name . . .
Because it is a gamma emitter it is fairly easily detectable. They would have discovered the cause very early because a standard Geiger counter would have picked up the radiation. Gamma radiation is not shielded by flesh, clothing, glass, air like alpha radiation is.
I would think the very short half-life of Po-210, 138 days versus 431 YEARS for Americium would make it far more attractive as an assassin’s tool: every 4 months your chances of detection are cut in half. And, as you pointed out, Po-210 is an alpha emitter, while Am emits both alpha and the far more easily detectable gamma.
No because the decay rate of the alpha particles is much different. In other words, it might take MUCH more Americium to generate the same amount of alpha particles per second and it is the release of those particles that kills. So polonium as a much shorter half-life, it is releasing thousands of times more alpha particles during that time and is therefore much more toxic.
CP,
But we are talking tenths of a gram versus millionths – BFD. It would make a good cover for the Po-210 (as would Thallium).
Americium would be most likely used for a dirty bomb. It probably wouldn’t harm very many but it could panic millions. People are afraid of ANY radioactivity (witness the recent release of ONE BILLIONTH of the allowable radiation from a Japanese nuclear plant recently).
While there is a small amount in smoke detectors, it would take quite a large number of them. In fact, the Brits caught someone attempting to do just this back in 2004:
http://www.time.com/time/magazine/article/0,9171,1101041011-708959,00.html