According to the United Nuclear web site, the only alpha source legal to possess in the US without a license is Polonium 210. Furthermore, I note
that if you buy this source you only get 0.1 uCi wheras the other sources have 1 to as much as 10 uCi for a comparable price.
I also read somewhere that tritium is not legal to posess in the US for private individuals. This is a very low energy beta emitter.
OTOH, there are plenty of (presumably legal) gamma emitters to choose from.
So why would this be the case? I always thought alpha was the least dangerous form of radiation and gamma by far the most dangerous.Mr. Wizard - 18-11-2004 at 17:10
I don't know why the alpha sources are hard to get, expensive, or illegal, but they are definitely not less dangerous, just dangerous in a
different way. Although the Alpha radiation, a Helium nucleus, is stopped by a few inches of air, a piece if paper or some other minimal shielding,
it is still extremely dangerous if it gets inside a living organism, say as a dust on the surface of the lungs or mixed with food and incorporated
into your cell structure, or under your skin where it can cause cancer and cause all sorts of problems, just like it's 'long legged'
cousins Beta and Gamma. Alpha particles are highly ionizing, and can do terrible damage to living cells. It is also rather hard to detect at a
distance by the normal "Geiger Counter" type detectors. The Alpha detectors have a very delicate film on them, and almost have to touch the
object to detect the Alpha output. If they touch an Alpha source, they are almost useless until they can be cleaned. Some Alpha emitters also put out
other radiation, so they can be picked up by the secondary or from daughter products, by a Geiger type tube. Don't underestimate these sources.
Alpha radiation can also stimulate neutrons from other materials, Beryllium for example. With neutrons you really get into the realm of Alchemy ;-)
Maybe that's why they are hard to get?JohnWW - 18-11-2004 at 17:37
"Alpha radiation can also stimulate neutrons from other materials, Beryllium for example." In fact, the action of radium-226, an
alpha-emitter, on beryllium-9 is the standard method for generating neutrons, e.g. for neutron activation analysis, and for making heavier isotopes of
elements.
In general, the heavier the radioisotope, the more energetic (and dangerous) is the radioactive emission. This is why the energy of the betas emitted
by tritium is so low.HNO3 - 18-11-2004 at 18:54
Tritium can be used in thermonukes, so that's probably why it's banned. Anyway, its a stupid law. Besides, it can be found in
glow-in-the-dark gun sights.neutrino - 18-11-2004 at 20:27
I seriously doubt that that one large-scale use of the stuff would warrant a massive ban on it. I think it’s just due to the fact that it’s a
radioactive <i>gas</i>, so if it is released, it could (theoretically) be relatively dangerous.Oxydro - 19-11-2004 at 04:14
Quote:
Originally posted by neutrino
.... I think it’s just due to the fact that it’s a radioactive <i>gas</i>, so if it is released, it could (theoretically) be
relatively dangerous.
That may well be the case, but it's kind of ridiculous, don't you think? How long does a gas like tritium hang around for, really? As
opposed to something like radon, which is heavy enough to accumulate in basements etc. I suppose if you react tritium with anything you could get some
nasty radioactive compounds ( "super-heavy" water, anyone ?) but that
automatically removes the whole uniqueness of the fact that it's a gas!neutrino - 19-11-2004 at 14:46
I suppose that I'm just a man of too few words... What I was thinking was along these lines: tritium is released into the atmosphere, you inhale
some, some decays in your lungs, more sticks around after diffusing into your bloodstream and you get cancer.HNO3 - 18-12-2004 at 09:06
When tritium is realeased into the atmosphere, it goes up (hydrogen, get it?),
so much doesn't hang around.vulture - 18-12-2004 at 13:30
Polonium has to be legal otherwise all tobacco products should be banned. I don't know why, but for some reason tobacco contains a much higher
concentration of polonium than anything else.HNO3 - 18-12-2004 at 16:41
IIRC, tobacco plants also absorb the uranium in the phosphate fertilizers applied to them. Then you have a beta emiter in your lungs...very
healthyJohnWW - 19-12-2004 at 01:53
The same plants that selectively absorb Se, of which there are many, can be expected to also similarly absorb Te and Po.
Go to the junk shop!
Dr. BOOM - 20-12-2004 at 01:28
try finding some 1970's fire alarms and rip out the ion chambers! You will get an excellent alpha.beta source that will do 40,000 CPM on a
gammascout rad meter.
Americum 241 is VERY active material** worse than Radium.
or you could look for photographers Uranyl Nitrate..sometimes sold on ebay or at speciality shops. Its moderately radioactive beta emitter.
Allof these sources are legal and can be bought without a licence.HNO3 - 20-12-2004 at 16:28
Dr. BOOM: nice try!
Radium is a high energy gamma emitter and if IRC alpha and beta too, and americium is alpha and *very* low energy gamma emitter, or it wouldn't
be used in smoke detectors. However, even modern smoke detectors contain it, but in milligram quantities.neutrino - 20-12-2004 at 18:19
He might have been referring to the rate of particles being emitted, and not their energies. Am-214 emits particles ~3 times as fast as the
corresponding sample of radium.Marvin - 20-12-2004 at 23:16
Dr BOOM is correct about everything except the beta emission.
A modern ionisation based smoke detector will also be fine. While they are legal to buy, it is illegal to remove the source.
Radium last I looked was alpha only, but it has some short halflife daughters that produce a lot of beta and gamma. I figure the amount of Am in a
smoke detector is more like nanogram amounts.Nick F - 21-12-2004 at 04:59
IIRC, I calculated the amount to be about half a microgram (L*T(1/2)=ln2, A=LN...). Or maybe I calculated power output to be about half a microwatt.
Hell, I can't remember! There's not much, anyway. A guy on ebay was selling a milligram sample a year or so ago, I think it went for about
$200.
Fairly large activities of polonium can still be had as anti-static brushes, I've seen 100uC! So that's a good alpha source. For gamma, try
thorium compounds, gas mantles, or old camera lenses. I have a lense about 3/4" accross that's hotter than six mantles! Or extract thorium
out of welding rods using electrolysis or H2O2. Then a mm of Al will shield out alpha and beta. A pure beta source is more difficult. Uranium
compounds are good beta emitters, but there's gamma in there too. Maybe K40 could be seperated as some sort of crown ether complex with
fractional crystalisation..? Would be a nice experiment!HNO3 - 21-12-2004 at 11:38
Any more details on how to purify thorium? I've got welding rods and gas mantles.Dr. BOOM - 21-12-2004 at 15:26
Quote:
Originally posted by Marvin
A modern ionisation based smoke detector will also be fine. While they are legal to buy, it is illegal to remove the source.
I have several older firealarms some with larger than usual amounts of Am 241, and some with Radium. They are all over the "safe" level of
activity...say 40,000 CPM---- I have one source that measures 81,500 CPM on alpha ---- its a Radium source.
The UBC physics guys help measure the activity with their Geiger counters--- they got rather interested really fast
BAAADDD. Very BAAADDD indeed... i'd be willing to sell it .... jokin'
of course.HNO3 - 21-12-2004 at 15:39
Where did you get these detectors?Dr. BOOM - 22-12-2004 at 02:15
A local junk shop of course.
Hey HNO3, you want one of these sources sent to you? I'll gladly go searching for one...
[Edited on 22-12-2004 by Dr. BOOM]HNO3 - 22-12-2004 at 09:52
A radium source would be nice. My lab boss authorised my to go up to $30 fro the source and S&H.
a newby posting here: not a newby to experiments
J-scan - 22-12-2004 at 10:21
Hey...that man is telling the truth. Those 70's Firealarms are wickedly radioactive. It can't Am241----its just too darn hot. I have a few
older radioactive sources but nothing that comes close to 81,000 CPM ---- several of mind are in the upper 60 K range. Some older ion chamber had
double sources and those could hit the 80 k range.
It is ILLEGAL to send those types of sources through the mail system unfortunatelyHNO3 - 22-12-2004 at 10:32
Bummer. I guess I'll have to make a container out of my 1/2" thick lead plate and ship it to Dr. BOOM with my money order. At which point
he'll put the detector in and crimp it shut and ship it back to me. Oh,
and I never knew it was illegal, either.
Check out his shipping methods. http://www.theodoregray.com/PeriodicTable/Elements/090/index...J-scan - 22-12-2004 at 10:35
activity is beyond what any mail courier system would allow.. sorryHNO3 - 22-12-2004 at 12:16
The obvious solution: I'm shipping some lead to a costumer. With an innocent face, of course.neutrino - 22-12-2004 at 17:22
Quote:
Originally posted by J-scan
activity is beyond what any mail courier system would allow.. sorry
And yet, United Nuclear ships their 40,000 cpm Am-241 sources (1uCi) via ups…HNO3 - 24-12-2004 at 08:51
You could ship a Alpha-only source in an envelope if you wanted to, since the paper would stop the radiation. Radium, however, is totally
different.....neutrino - 24-12-2004 at 11:31
Makes sense... but don't forget that Am-241 is also a gamma emitter.
edit: Just a thought: if you're in the US and shipping anything radioactive without a good reason, you might be labeled a terrorist.
[Edited on 24-12-2004 by neutrino]HNO3 - 24-12-2004 at 21:07
'Alpha-only source'
I know Am-241 is a gamma emitter, but, IIRC, it is a low level gamma emitter. That means that its emitions are stopped by thinner materials than the
high level gamma emitters. That's why its used in detectors.
But if they can't detect any radiation from the box, they can't really say they had enough evidence to open it. See my earlier link for an
example.
) but that
automatically removes the whole uniqueness of the fact that it's a gas!
),
so much doesn't hang around.
