Sciencemadness Discussion Board - Radioactive Chemistry

Radioactive Chemistry

SulfurApothecary - 11-7-2012 at 19:09

I was wondering if anyone have tried radioactive chemistry at home? I know that americium is in smoke detectors (alpha emitter) radium in luminous clocks (alpha emitter) thorium dioxide in lantern mantles (alpha emitter). I think it would be interesting to try to do this at home, but the dangers would be somewhat great considering inhalation hazards, and the fact that anyone who made gammer emitters it could pose a public health risk. Now I do know that you can take an alpha emitter and take aluminum and then bombard it would alpha particles, then one could produce neutrons. From this someone could take this and make more radioactive elements. Paraffin could be used to slow down neutrons as well as water. But even better than aluminum is beryllium, its just that it is harder to get. Another thing that one could get is tritium that could emit beta -.

So in conclusion it is interesting that one could actually get their hands on radioactive materials, for experimentations.

(Lithium could be used to isolate thorium from thorium dioxide).

Endimion17 - 12-7-2012 at 00:51

You're talking about transmutation? If you knew anything about it, you wouldn't ask such questions. It is completely out of reach for a home chemist with even a good protective equipment.
Unless you don't care about your life, and the life of people in your vicinity.

The point is that in order to make measurable concentrations of the new stuff, you've really got to have a good source of particles.
Also, I suppose you don't have a mass spectrometer at home, therefore to detect anything with typical crude methods (even the best typical analytical ones are crude compared to mass spectroscopy), you'd have to really pile up lots of the initial stuff, and that means contamination and a waste of money. People have done it before (Hahn et al.

) and they really messed things up.

The only radiochemistry safe enough to do is small scale analytical. For example the properties of solutions of radioactive elements, given that their radioactivity is not great. For example uranium-238 salts in small quantities won't harm you if you hold on to strict procedures because the danger is in the absorption of the atoms, not few measly rays.
However any messing with radium will fuck you up.
Therefore, analytical radiochemistry of weakly radioactive elements. But transmutation? Don't even try it. It's truly out of safe reach.

To do anything measurable, you'd have to resort to the Curie methods, with buckets and acids and all that. Just don't.

[Edited on 12-7-2012 by Endimion17]

DoctorOfPhilosophy - 12-7-2012 at 01:47

Transmutation can be done on a DIY cyclotron. A select few people have actually taken the time to build one, so you might wanna contact them and ask to borrow

Yes Hahn screwed up big time. I'm assuming you don't mean to do a large scale experiment though (I hope not). Curie method is also high inadvisable (esp. strapping a gram of radium to your arm for a month)

In my humble opinion, it is unfair to make general statements about the safety of gamma radiation or radium chemistry. Yes one must be extremely careful, but any experiment can be done safely if the scale is small enough!

I have a section on my web page dedicated to chem with technetium/promethium/polonium/thorium/radium/protactinium/uranium/americium. This is the link, take a look if you're interested. The only reason I haven't done any is because I can't choose a Geiger counter. USE A GEIGER COUNTER! Not something you wanna save money on.

Endimion17 - 12-7-2012 at 04:02

Quote: Originally posted by DoctorOfPhilosophy

Transmutation can be done on a DIY cyclotron. A select few people have actually taken the time to build one, so you might wanna contact them and ask to borrow

By Curie method I meant working with large amount of materials. They've concentrated their stuff. I can hardly imagine the amount of particle flux needed to make a measurable trace of some new element. These things are done in real reactors and cyclotrons with high fluxes.

Quote:

In my humble opinion, it is unfair to make general statements about the safety of gamma radiation or radium chemistry. Yes one must be extremely careful, but any experiment can be done safely if the scale is small enough!

Radium is so intensively radioactive that any concentration of its salts large enough to be detected by any method other than a Geiger counter, would be very dangerous. Even a slightly visible precipitate of its carbonate is enough radioactive to pose a danger of acute burns through the test tube. It glows, and the air surrounding it glows, too, indicating its furious decay.

The danger of the rays exists as a lone fact if the stuff is sealed. But if you do any experiments with it, you will get yourself contaminated. It is absolutely impossible to do any experiments without getting yourself contaminated. Just think of that damn sodium that is a nuisance in spectroscopy even in minute, trace concentrations. Well while those concentrations are ok for sodium, they present an acute radiotoxic danger for radium.
Given that the amount are not macroscopic, i.e. detectable by a counter only, the only way to do it would be in a lead glovebox with disposable microscale equipment, for example plastic eppendorf tubes.

Any precipitation obviously means there's an extreme radiotoxic danger.

It is simply not something you want to do if you don't want to die too early.
Here's a video showing how things are not supposed to be done. It's actually incredible how the hell YouTube didn't remove it. Check out my comments - the guy is obviously ignorant and cocky, thinks he's smarter than everyone else.
His house is probably contaminated now. It's not radium, but yellowcake, but it's dangerous nonetheless.

blogfast25 - 12-7-2012 at 04:52

Any form of experimenting with radioactive materials in appreciable quantities in a home setting, w/o proper tried and tested safety features and w/o peer review is simply a recipe for slow and painful suicide/murder.

[Edited on 12-7-2012 by blogfast25]

DoctorOfPhilosophy - 12-7-2012 at 04:57

Most home-built cyclotrons are about 12" - 14" in diameter (http://cyclotronconference.org/). A 37 inch cyclotron was used to prepare the first sample of Tc-99m. It's hard to say how much technetium would be produced by a 14" cyclotron, but even if it's a nanogram it can still be eluted in a chromatography column. The question is, would the Geiger counter be sensitive enough to pick up the radiation. I know DIY neutron activation is a tried and tested experiment (http://carlwillis.wordpress.com/2008/02/17/farnsworth-fusor-...), and some isotopes quickly decay to another element. That's an indirect transmutation. Of course you will not get a gram or milligram quantity, but something detectable.

I absolutely agree that large scale production is a bad idea, but let's give some numbers to the concepts instead of using weasel words.

Needless to say, if you see a radium salt precipitating from a solution, then it's a miracle your still alive. However, using your brain, a capillary tube, and a centrifugal evaporator, you should be able to safely produce no more than a microgram. Here is my logic:

Natural uranium has a specific activity of 25,280 Bq/g. Radium is 3.66x10^10 Bq/g. In Canada, the maximum amount of natural uranium an average joe can have lying around without a license is 15kg. That has the same activity as 10.36 milligrams of radium. Both are alpha emitters. Unlike radium salt though, the uranium shields itself. And it isn't water soluble. And it's VERY hard to loose. In other words, 10 mg of radium PERFECTLY SEALED would be safe in big lead block, but should the seal break, you and your town are going straight to Utah.

Consider 10ug of radium, equal to 15g of uranium. It's the smallest amount you could probably see with the naked eye. 15g or uranium wouldn't do much harm outside you, but if a water soluble salt (e.g. uranyl nitrate) got into you, its more likely than not going to kill you. Nevertheless, people like Theo Gray have about that much uranyl nitrate at home, safely. The big difference is it's a lot easier to loose a grain of salt than 15g of powder.

If you are a responsible person doing things properly and not in a Home Depot bucket, I think up to 1ug of radium (1.5g U equivalent) is reasonable. You can see the crystal under a descent microscope, and even if by some stupid freak accident you did swallow it, you will have just hurt yourself really. The worst thing would be to drop it on the floor, but you can always find it with a Geiger counter. In fact, if you check all you equipment and work area with a Geiger counter, you can find contamination before your house becomes a superfund site.

That's just my opinion though, I'm certainly not recommending anyone to try unless they personally think it's a good idea.

blogfast25 - 12-7-2012 at 05:08

Quote: Originally posted by DoctorOfPhilosophy

That's just my opinion though, I'm certainly not recommending anyone to try unless they personally think it's a good idea.

No, and going by your site I'm not recommending you try it either. Try crawling before walking: there's plenty interesting home chemistry around before having to dream up schemes that involve highly radioactive materials and microchemistry (an art by itself).

blogfast25 - 12-7-2012 at 05:36

Quote: Originally posted by Endimion17

Here's a video showing how things are not supposed to be done. It's actually incredible how the hell YouTube didn't remove it. Check out my comments - the guy is obviously ignorant and cocky, thinks he's smarter than everyone else.
His house is probably contaminated now. It's not radium, but yellowcake, but it's dangerous nonetheless.

Not to mention his swimming pool!

Totally bonkers. On a much smaller scale, with adequate precautions, it might be able to do this safely, if you have access to low radiotoxic waste disposal services. I'm guessing he chucked most of his debris with the household waste too! D*ckhead Supremo, indeed!

Endimion17 - 12-7-2012 at 05:51

The only radioactive chemistry suitable for a very experienced home chemist that received his knowledge by reading proper books, and not by browsing the Web and watching YouTube, is one of depleted uranium and perhaps thorium.

Uranium-238 salts are available in small quantities as a reagent. Its radioactivity is meek and it's used in analytical chemistry without special precautions needed for handling more active stuff.
If you ensure you're wearing gloves and you're washing your glassware thoroughly, you can do fine even with larger precipitates (few grams). General caution applies like when handling mercury salts, therefore it surpasses skills of the most of forumers here.

However if you're a typical YouTube-experimenter that uses plastic cups, soda bottles, doesn't wear gloves, picks his nose, stay far away from it. I'm not pointing fingers now. I'm adressing to anyone who reads this. You will contaminate yourself with a radiotoxic heavy metal.
It's obvious home experimenters' bodies are having a larger than average intake of poisons. Keep the contamination in the reasonable range such as typical heavy metals, organic solvents, oxidizers.

Quote: Originally posted by blogfast25

Quote: Originally posted by Endimion17

Well it's not the swimming pool I'm worried about. Dudes are drying the yellowcake with a fan heater. They're blowing hot air over it.

The stuff is apparently >40,000 CPM over a plastic bag and they're blowing into the sand and dust like particles. What a waste of protective equipment. D:

I'd mix the waste with concrete and make a block. The usual method.
If it's embedded in the concrete, you can throw it in the dumpster. Nobody would notice and nobody would suffer. It's natural uranium. This guy, on the other hand, could just throw it back to the mine from which he took the ore. He even mentions it in the comments. So that's ok. But the drying and the initial chucking of the high activity ore like it's a piece of regular rock... stupid.

[Edited on 12-7-2012 by Endimion17]

blogfast25 - 12-7-2012 at 06:07

Where are your comments, Endimion?

Endimion17 - 12-7-2012 at 06:51

Check the "see all", they're quite old, almost as the video itself.

Wizzard - 12-7-2012 at 06:54

@Endimion- What's wrong with picking one's nose??

And that video about the Uranium on Youtube- That's some scary bad DIY chemistry- I'd hate to see what his did with all that radioactive contaminate.

blogfast25 - 12-7-2012 at 07:31

Love his straw man counter-comment:

"Contrary to what you might think, the United States has established acceptable exposure limits for insoluble uranium compounds, none of which could be expected to be met considering the quantity of the sample prepared, physics properties of the sample, time spent handling the sample, and radiation detected around the lab with a very sensitive meter (not significant over background). There was absolutely no reason to believe that any industrial safety standards were violated."

Except he hasn't measured anything. At least not properly...

vmelkon - 12-7-2012 at 08:20

Quote: Originally posted by SulfurApothecary

I was wondering if anyone have tried radioactive chemistry at home? I know that americium is in smoke detectors (alpha emitter) radium in luminous clocks (alpha emitter) thorium dioxide in lantern mantles (alpha emitter). I think it would be interesting to try to do this at home, but the dangers would be somewhat great considering inhalation hazards, and the fact that anyone who made gammer emitters it could pose a public health risk. Now I do know that you can take an alpha emitter and take aluminum and then bombard it would alpha particles, then one could produce neutrons. ...

Here's my experiment
http://www.youtube.com/watch?v=Huzb0hs4Bcc

blogfast25 - 12-7-2012 at 09:01

So, assuming that the difference in the counts is actually statistically significant (it's hardly a rigorously controlled experiment...) you may have transmutated a few atoms of Al...

Endimion17 - 12-7-2012 at 09:08

Quote: Originally posted by Wizzard

@Endimion- What's wrong with picking one's nose??

Nothing at all. I do it all the time, but not while I'm in the lab... and not while anyone can see me.

Quote: Originally posted by blogfast25

Love his straw man counter-comment:

"Contrary to what you might think, the United States has established acceptable exposure limits for insoluble uranium compounds, none of which could be expected to be met considering the quantity of the sample prepared, physics properties of the sample, time spent handling the sample, and radiation detected around the lab with a very sensitive meter (not significant over background). There was absolutely no reason to believe that any industrial safety standards were violated."

Except he hasn't measured anything. At least not properly...

Technobabble with a style that reminds me of politicians.

I'd buy him a cat. It would walk around the contaminated floor, licking its paws occasionally, like cats do.
He could measure the activity of its dried urine each week. That would be a fun thing to do.

blogfast25 - 12-7-2012 at 12:46

Quote: Originally posted by Endimion17

Technobabble with a style that reminds me of politicians.

Or 'salesmen' of 'HHO' jam jars...

It shows that getting lots of UToob hits isn't that difficult: do something daring badly (his yellowcake looks decidedly dodgy) and presto... the dumb faithful adore you!

[Edited on 12-7-2012 by blogfast25]

DoctorOfPhilosophy - 12-7-2012 at 18:29

First off, I absolutely and vehemently disagree with everything done in the (first) video, and the quote does sound like quackery. Having said that, I have to play the devil's advocate here.

A lot of people look the same way onto amateur chemistry. I can totally imagine some concerned parents on the news saying that they were "shocked" and "horrified" when they police discovered a sulfuric acid electrolysis cell in their neighbors basement. Many people have many opinions on what's safe and what isn't.

Not to be overly rash, but I'd say if you don't want to sound like the typical anti-chemistry propagandists, look for some numbers or figures that actually support your assertions. Just saying " that's dangerous but this isn't " is politics, not science.

[Edited on 13-7-2012 by DoctorOfPhilosophy]

[Edited on 13-7-2012 by DoctorOfPhilosophy]

Boron Trioxide - 12-7-2012 at 21:15

Just my contribution:

http://www.youtube.com/user/bionerd23
Someone's youtube channel mostly about radioactivity.

http://unitednuclear.com/index.php?main_page=index&cPath...
Everyone should know about united nuclear and what they sell.

If you already knew about these things then I am sorry for wasting your time.

vmelkon - 13-7-2012 at 08:28

Quote: Originally posted by Boron Trioxide

http://unitednuclear.com/index.php?main_page=index&cPath...
Everyone should know about united nuclear and what they sell.

united nuclear is a nice site, but they are US based. I asked them if they had ever shipped their mineral samples to Canada, and they said every single one of them has been confiscated.
http://unitednuclear.com/index.php?main_page=index&cPath...

I had also contacted Canada Post. A lady called and left a message saying that Canada Post doesn't want anything to do it and to use another shipping company.

So, I wonder how come their are able to ship within the USA.

DoctorOfPhilosophy - 13-7-2012 at 13:05

If it's radioactive, they'll detect it in no time. You could use that to your advantage though, there are lots of radioactive rocks in Canada so it shouldn't be too hard to find a bit of uranium

I've ordered beryllium from United Nuclear (they had the best price) and it got here alright

rannyfash - 13-7-2012 at 18:41

I wanted to accelerate alpha particles from americium with an electrostatic field in a vacuum to a thin film of aluminium and with lead shielding focus the neutrons into a beam and irradiate a small piece of lithium coated with a thick clear expandable phosphorescent polymer.

neutrons would be captured by the small percentage of natural Li 6 and would fissure releasing an alpha particle and tritium the radioactivity of the tritium would then cause the phosphor to glow.
although keep in mind that this is a half baked idea and i have not fully looked at the practical implications as i ruled it out as a safe feasible reaction as many of you should also come to terms with the brutal fact that you would be risking your life experimenting with a non-visible force albeit i think it could be done at home but only with an almost none existent margin of error, i have no practical experience on this subject.

blogfast25 - 14-7-2012 at 03:50

Quote: Originally posted by rannyfash

i have no practical experience on this subject.

Then stay clear or very SERIOUSLY read up and TOOL up. On second thought, just stay clear. :cool:

Endimion17 - 14-7-2012 at 04:23

Quote: Originally posted by blogfast25

Quote: Originally posted by rannyfash

i have no practical experience on this subject.

Then stay clear or very SERIOUSLY read up and TOOL up. On second thought, just stay clear. :cool:

I don't think anything can happen to him. The flux is ridiculously low. That's physics what he's trying to to.

DoctorOfPhilosophy - 14-7-2012 at 05:54

Quote: Originally posted by rannyfash

I wanted to accelerate alpha particles from americium with an electrostatic field in a vacuum to a thin film of aluminium and with lead shielding focus the neutrons into a beam and irradiate a small piece of lithium coated with a thick clear expandable phosphorescent polymer.

See on the physics forums if someone built a Farnsworth Fusor anywhere near your area. Maybe you can use that to do your experiment. Hopefully the same person would know enough about physics to stop any dangerous ideas.

vmelkon - 14-7-2012 at 09:56

Quote: Originally posted by DoctorOfPhilosophy

If it's radioactive, they'll detect it in no time. You could use that to your advantage though, there are lots of radioactive rocks in Canada so it shouldn't be too hard to find a bit of uranium

I've ordered beryllium from United Nuclear (they had the best price) and it got here alright

I don't have a car

Beryllium is not a problem since it is not radioactive.

SulfurApothecary - 14-7-2012 at 12:47

Beryllium is better than aluminum for neutron generation.

kristofvagyok - 14-7-2012 at 14:55

Transmutation of elements is a really good fun on paper, but not in a garage.

I have also thought it a lot, how awesome would be to make some "not often seen compound", but it would be extremely hazardous and even in a proper lab it could cause problems.

First problem: neutron generators.

It wouldn't be some hard to get some beryllium, it could be ordered from ebay (I also found a few hundread gramms of BeO in the lab

), but a proper alpha emitter is really hard to get.

Am, Th is the most "OTC", but the Th is not as active as it should be and it has a relative large neutron cross section, so it would absorb almost all the neutrons generated. The Am would be good, but really small quantities are used everywhere and hard to get more than a few microcuries.

Ra sucks, it is not used in the past few (ten) years and in old "clocks" as seen in the radiactive scout kid are not as active as they should be.

The best would be to get a small lump of Be, melt its surface and add some americium salt. With 5-8micrucurie Am doped properly in the Be, pretty things could be done

Also there is another method getting out some neutrons from Be and D2O, with some high energy photons.
9Be + >1.7 Mev photon → 1 neutron + 2 4He
2H (deuterium) + >2.26 MeV photon → 1 neutron + 1H

Here is also a problem: proper shielding from gamma rays (and I even don't know where to get a high energy X-ray tube).

The other thing: the neutrons should be slowed down (to make transmutation), so some hydrocarbon solvent or water should be used and it is also a practical thing if you have a proper shielding from these stuff, so a "usual" breaker would be a deadly choice...

And some reminding:
1 Ci = 3.7 × 10^10 decays per second, while mole is 6x10^23 and not every neutron finds the atom where it should go.

SulfurApothecary - 14-7-2012 at 15:14

United nuclear you can get high energy x-ray tubes. Yes I know that it is improbable but if one would become very obsessed with the project you could get a neutron gun. The problem with D2O is that its just about worth its weight in gold, so it would be hard to do that.

kristofvagyok - 14-7-2012 at 15:24

Quote: Originally posted by SulfurApothecary

The problem with D2O is that its just about worth its weight in gold, so it would be hard to do that.

Maybe D2O is not as expensive as people think it is(:

Also: Xray tubes from UnitedNuclear is for girls making scans from a pink barbie girl in the plastic house.

1MeV or stronger photons could be generated from Xray tubes what are working with a fewMV (million Volt) accelerating voltage.
Also these photons could be stopped with a massive block of lead (few inches) and it could be easily fatal. Not joke.

[Edited on 15-7-2012 by kristofvagyok]

Lambda-Eyde - 14-7-2012 at 15:38

Heavy water is not that expensive, it's just expensive in the amounts needed for practical experiments and not just as a nice keepsake/curiosity.

blogfast25 - 15-7-2012 at 06:01

I really think this is all hypothetical unless you have the equipment, safety precautions and instrumentation to monitor what you’re doing and what little transmutated materials you may have obtained. It seems a helluva of expenses and risk to obtain unweighably small amounts of something, just to be able to say: ‘I did that’…

Even during Fermi’s ‘ CP-1 criticality experiment very little actual Pu-239 will have been formed due to short irradiation times at high neutron flux.

DoctorOfPhilosophy - 15-7-2012 at 19:10

Heavy water should be about 600-800 USD /kg on the market, or 1 USD /g in small quantities. Can you do anything useful with it, that's the real question.

vmelkon - 17-7-2012 at 06:52

People who build a farnsworth device buy D2O and do electrolysis. You just need a small amount of D2 gas in the "fusion chamber". It does emit neutrons, but the flux is low.
Search for fusor on youtube.

unionised - 17-7-2012 at 13:03

Quote: Originally posted by SulfurApothecary

Beryllium is better than aluminum for neutron generation.

Yes and it still has a success rate of something like 1 neutron for each million alphas.

Incidentally, I don't think the alphas from Th or U have enough energy to get neutrons from Be.

Mildronate - 17-7-2012 at 13:07

I had Pb gloves and 300mL D2O at home, but i never use.

Mildronate - 17-7-2012 at 13:10

yes also i have xray lamp

DoctorOfPhilosophy - 17-7-2012 at 13:49

Here's an article on neutron activation. The author managed to activate gallium, antimony, europium, bromine, indium, manganese, gold, vanadium, aluminium, and iodine.

Radon 220 from Thorium

annaandherdad - 12-10-2012 at 07:46

This thread is very interesting. I was trying to research chemistry issues regarding thorium, which came up as I was trying to think of a good way to obtain radon 220.

I was motivated by the youtube post by bionerd23, http://www.youtube.com/watch?v=Efgy1bV2aQo
in which she demonstrates the double alpha decay of radon 220 in a cloud chamber. I was astonished by the educational aspects of this demonstration, and would like to do it for myself, so that not only I can see it but also my daughter and possibly other children. Depending on how I assess the dangers, I may not do it at all, or do it just for myself, or for others as well. We shall see. In any case, I intend to build a cloud chamber, which is useful for viewing cosmic rays and small radioactive sources.

About the educational aspects. This (bionerd23's) demonstration shows: 1. diffusion of a gas (radon) injected into air. One can immediately see the atoms diffusing across the chamber. 2. The alpha decays (also seen with any alpha source in a cloud chamber). 3. The double decay, Rn 220 -> Po 216 -> Pb 212. The Rn 220 has a half life of 55 sec; Po 216, 1/7 sec. See http://en.wikipedia.org/wiki/Decay_chain#Thorium_series
for the basic data on the decay chain. Sometimes a Po 216 atom takes longer to decay, and you can see the origin of the second alpha has shifted from the first; the V is split at the base. 4. One sees directly the randomness in the directions of the emitted alphas (the V's don't all look the same). 5. One sees the activity decrease over a minute's time as the Rn 220 decays. There are also other educational aspects.

Obviously to do this demonstration one needs a source of Rn 220. Given its half life, it must be made within minutes of its use. That means a sample of thorium must be obtained, which has been around long enough for its daughter decay products to have reached an equilibrium population. Since the daughter product with the longest half life is radium 228 (5+ years), this means a sample of thorium that has been sitting for some number of years after its chemical purification (if any).

Here is a definite advantage of thorium over uranium for certain purposes: The decay chain of uranium contains isotopes with lifetimes long on a human time scale, whereas for thorium the maximum is 5.75 years. In fact, in the thorium decay chain, the only isotopes with a life time of more than 1 year are radium 228 and thorium 228. So if one takes a sample of thorium that has been sitting around long enough to achieve equilibrium quantities of decay products, then the only components with a half life of a year or more are thorium and radium. All others have a half life of less than a day, most much less than that. So if one does a chemical separation of thorium from radium, the rest of the radioactive sludge will decay to harmlessness in a few days. As for the radium component, it will decay to harmlessness in a few decades. This is a lot better than the americium in smoke detectors, which people regularly throw in the trash, which has a half life of 450 years or so. The rest is thorium 232, with a half life of 14 billion years. It will remain ordinary, radioactive thorium forever.

Now why would I want to chemically separate the thorium from the radium? I'm not sure I do, but I've been thinking about it. After seeing bionerd23's demo, I bought 5 grams of thorium nitrate from ebay. This may have been a little hasty, as I realized I would have preferred thorium oxide, since it is insoluble in water. I haven't weighed my sample, but if I accept the seller's quote of 5 grams, then I have about 2 grams of thorium, which has an activity of about 8 kBq for each isotope in the decay chain. There are roughly 10 of these, so I've got a total activity of maybe 80 kBq, assuming this sample of thorium nitrate has been around for a decade or two, which seems likely since it looks like it came from an old lab. To put this in perspective, a normal smoke alarm has maybe 40 kBq of activity. People routinely throw these in the trash, not that I'm saying they should, but just to put this in perspective.

Now to obtain some radon 220, I could just draw off some of the air above the thorium nitrate. I was thinking of putting it in a bottle with a rubber diaphragm across the top, like doctors use for vaccines. and using a syringe to withdraw some air, which could then be injected into the cloud chamber. Of course this will make the cloud chamber radioactive, but only for a day or two until everything decays to Pb 208.

But here is a possible problem. Radon is a gas, but when it is produced inside a crystal of thorium nitrate, presumably some of it (most of it?) does not escape to the air. So will I have enough radon gas above my sample to use? Without trying it, I don't know how to estimate this. But it seems logical that if I had my thorium in the form of a powder, eg thorium oxide, then more of the radon would escape. This was why I was starting to regret having ordered thorium nitrate instead of thorium oxide.

Well, why not convert my thorium nitrate to oxide? (I'm starting to think about it, anyway.) That shouldn't be hard to do (ammonia, maybe, to the hydroxide, then heat). Well, one reason not to do this is that this will precipitate out the thorium, thereby purifying it from its decay products, notably, the radium. So I'll get a chemically pure sample of thorium oxide, and I'll have to wait 5 years or so before I start to get my radon 220.

Obviously the easiest thing to do would be to buy another sample of thorium, this time, thorium oxide, making sure it has been around for decades since any chemical purification. (An old Coleman lantern mantle?) But bear with me, even if my chemical separation is not needed or practical, this situation is making me *think* about it, even if I never do it.

One worry in any such chemical separation is creating a radioactive mess that would contaminate my lab and me and everything all around. But, remember, only the thorium 232 has a long half life; the next worse is radium 228, with a half life of 5 years. One thing that became obvious to me is that before doing anything along these lines I'd have to have a geiger counter, to track any radioactive materials. They're pretty pricey for a good one (maybe $300 or more), which is more than I had planned on investing in this. But, like I keep saying, at this stage I'm just thinking. In any case, the short half lives of everything except thorium 232 and radium 228 makes this process a lot less scary than it would be for a similar exercise with uranium.

So, supposing for the sake of argument, that I wanted to take my thorium nitrate, convert the thorium to thorium oxide, and separate out the radium. The radium will be present in nanogram quantities, too small to see, but if I want to get the radon, and I don't want to wait 5 or 10 years, then I need to have that radium. Plus it will be easily detectable by its radioactivity.

Here's where some of the chemical expertise on this forum might help me. I assume that radium sulfate is highly insoluble in water, just like barium sulfate. So if I dissolve my thorium nitrate in water and add sodium sulfate, and filter, do I separate out the radium? Thorium sulfate (according to a little research) is reasonably soluble in water, so it should not precipitate.

Now, radium sulfate may be highly insoluble, but maybe a nanogram will dissolve in a few cc of water. I don't know the numbers. Now, I'm thinking, radium mimics barium, so if I add some barium nitrate (I'm thinking maybe 0.1 gram) to my thorium nitrate solution, then sodium sulfate, I will of course get a precipitate of barium sulfate. And will this not carry the radium sulfate with it? So I could filter, and I've got my radium sample. I don't care that it's mixed with barium, that doesn't matter. The point is that it will start to produce radon 220 immediately.

Actually, not immediately, this is a little tricky, and you have to refer to the thorium decay chain. The radium that is separated will contain both radium 228 and radium 224, with half lives of about 5 years and 3 days. It is the radium 224 that will start to produce radon 220, on a time scale of a minute or so.

Anyway, this is the trend of my thinking. I'm wondering what anyone here thinks about my naive ideas for separating nanogram quantities of radium from thorium nitrate.

[Edited on 12-10-2012 by annaandherdad]

phlogiston - 12-10-2012 at 11:38

Yes, the radium will co-precipitate with the barium sulphate precipitate. This is exactly what the Curies did initially.

Why not carefully crush the thorium nitrate to get a powder?

Why not heat the thorium nitrate directly to get the oxide, with the radium remaining in it?

The solution of thorium nitrate should release radon as well, but perhaps it will remain in solution and decay there.

annaandherdad - 12-10-2012 at 16:31

Quote: Originally posted by phlogiston

Yes, the radium will co-precipitate with the barium sulphate precipitate. This is exactly what the Curies did initially.

Why not carefully crush the thorium nitrate to get a powder?

Why not heat the thorium nitrate directly to get the oxide, with the radium remaining in it?

The solution of thorium nitrate should release radon as well, but perhaps it will remain in solution and decay there.

Yes, just heating the thorium nitrate is a good idea, it will retain the radium which I need. As for crushing the thorium nitrate, I was thinking that I might end up with smaller particles with thorium oxide, hence more radon. Mind you, I have no idea whether I will need more radon, it might be enough just out of the bottle I have. If I do end up crushing anything, I'm going to worry about inhaling dust.

Getting the radon out of the crystals where it is formed is obviously an issue in radon contamination of the environment. The isotope that comes from the uranium decay chain has a longer half life than radon 220, and so a longer time to escape its site of birth, but the issue is still there. I read somewhere that Iowa has high levels of radon, because ice age glaciers ground the granite to a fine powder and deposited it all over Iowa. So now the uranium in the granite decays to radon which gets in people's basements.

And thanks for the confirmation about the barium precipitation of radium. Where did you learn about the Curies? The only biographies I've seen were not very scientific, and didn't go into details.

I've also contacted bionerd23, maybe she has some advice.

borrowedlawyer - 13-10-2012 at 01:32

Remember a garage is not a place for transmutation of elements. If you want to do radioactive chemistry at home, stick to very small quantities of low - moderately radioactive elements/compounds, forget radium, holding a test tube with it would be enough to burn you.

annaandherdad - 13-10-2012 at 07:40

Quote: Originally posted by borrowedlawyer

Remember a garage is not a place for transmutation of elements. If you want to do radioactive chemistry at home, stick to very small quantities of low - moderately radioactive elements/compounds, forget radium, holding a test tube with it would be enough to burn you.

I'm just talking about nanogram quantities, or picograms. It's the radium which is present in natural thorium, in my case, a small sample. The total radium activity is 8KBq for the two isotopes.

Doc B - 14-10-2012 at 18:20

There is likely an untapped source of radioactive material in anyone's kitchen. Run a Geiger counter over any orange colored ceramic dish, plates or cups you have and expect a squeal.

annaandherdad - 14-10-2012 at 20:04

Yes, I'm looking into getting a Geiger counter. Can't do much without one, but I'm hoping to get something cheaper than the $350 new models out there. When I get one, I'm going to check out the kitchen, maybe some antique stores etc.

watson.fawkes - 14-10-2012 at 21:26

Radon is rather a heavy atom and rapidly diffuses downward in still air. If you're looking for is to see it in a cloud chamber, I think all you'd need to do is to put the solid Th compound into a mechanical configuration where radon can drop downward into the chamber. Since the Rn has to diffuse out of a crystal matrix, you'll want to make that distance small. Rather than grinding it, which will almost certainly cause lab contamination, I'd recommend a thin-layer coating. For example, take a glass tube and evaporate a solution of the Th nitrate on its interior. You'll need to continuously rotate the tube while it evaporates. Then orient the tube vertically over an inlet to the cloud chamber. If you need more surface area, you could coat 1mm glass bead, but you might need to use an argon flush gas to drive an Rn out of the generator before it decays.

phlogiston - 15-10-2012 at 02:09

Quote:

And thanks for the confirmation about the barium precipitation of radium. Where did you learn about the Curies? The only biographies I've seen were not very scientific, and didn't go into details.

Unfortunately, I can't recall exactly where I read a description of their method, but I am sure it is online.

However, from the Encyclopedia Brittanica guide to Nobel Prizes for instance:
http://www.search.eb.com/nobelprize/article-9435287

Quote:

When the mineral does not contain much barium, a certain quantity of barium salt is added in order to carry away the radium.

You may also find the following manuscripts interesting:

about radium/barium co-precipitation
http://www.google.nl/url?sa=t&rct=j&q=barium%20radiu...

And this bibliography of unclasified literature on radium by the american AEC
http://www.dtic.mil/cgi-bin/GetTRDoc?Location=U2&doc=Get...

Edit: Incidentally, in this last document you can also find a reference to a paper in which a thorium nitrate solution is occasionally boiled to release its radon gas (they were trying to demonstrate the appearance with time of radium in solutions of a thorium salt). IIRC its author was either Soddy or Hahn, somewhere near 1910.

[Edited on 15-10-2012 by phlogiston]

annaandherdad - 15-10-2012 at 06:48

Watson, thanks for your ideas on getting the radon out. I, too, have been thinking that it will be impossible to grind my thorium nitrate without contaminating my lab. Again I regret not having bought thorium oxide, since I don't like the fact that thorium nitrate is soluble, and I'm thinking the radon may escape more easily from the (powder) thorium oxide than the (crystal) thorium nitrate. Conversion of nitrate to oxide could be carried out by heating, as pointed out above, but before doing any of that, I'm going to just try it. That is, I will extract some of the air above my thorium nitrate (with a syringe) and inject it into the cloud chamber (which I have yet to build---that will be a project). There is no point fooling around with anything else before just trying the simplest thing.

Bionerd23 suggests that I get some thorium sands---monzanite--and place them in a rubber enema bag. Then use the rubber to push out some of the air into the cloud chamber. I could make some jokes but I won't. I'll probably try it my own way first.

By the way, radon gas, although heavy, should diffuse until it is nearly uniform over the extent of the cloud chamber. Its density in the earth's gravitational field will go as exp(-mgh/kT), with height h, which means that its density will decrease with altitude on a scale of several hundred meters (rough calculation in my head). Completely apart from the radioactivity, one of the things that astonished me about bionerd's video is the diffusion of the gas through the cloud chamber. Of course, one can open a bottle of perfume in a quiet room, but this is visually very dramatic.

Phlogiston, thanks very much for the references. I just read the EB article by Curie, in spite of the fact that the last couple words of each line are cut off. Perhaps the most interesting aspect was to be inside her mind for a moment. She mentions extraction of radon as a quantitative method of measuring the presence of small amounts of radium: dissolves the material in solution, and circulate air through the solution to pick up the radon. Her radon (from uranium), unlike mine (from thorium), lives long enough to make this practical.

She also mentions a re-solution of barium/radium sulfate by using sodium carbonate. Do you understand this?

My thinking about this whole idea at this moment is that if I can get a suitable sample of radon 220 by some easy method, then there is no point doing anything chemical with any thorium compound, apart from its educational value.

Nevertheless, the fact remains that it would be easy, chemically speaking, to separate thorium compounds from their small radium (228 and 224) components. And, in contrast to uranium, those are the only two elements in the decay chain that have life times more than a few hours. For a couple of grams of thorium such as I have the amount of radium is measured in nanograms or picograms, so you wouldn't be seeing it, but you could create a small sample of mostly barium sulfate that was much more radioactive (on a per-gram basis) than the thorium you started with. Plus, one could observe the activity of the radium as a function of time: In the first few days the radium 224 would decay, after that you'd have a decay of radium 228 on a scale of 6 years or so, with a build-up and then decay of thorium 228. It would be possible to create a sample (again, nanograms, at the most) of thorium 228, effectively separating isotopes of thorium by purely chemical means. BTW, Curie quotes a life time for radium 228 of 6.7 years, the current figure seems to be 5.7 years.

I spent some time solving the equations for decay chains with different decay times. As a practical matter, the disparities in the different decay rates means that one can understand those solutions intuitively without doing much work, because most time scales you want to name are either much longer or much shorter than the the life times of the various components. Still, the chemical separation of thorium from radium gives different initial conditions for the quantities of various isotopes as a function of time, and I'll post some graphs as soon as I can plot them.

phlogiston - 16-10-2012 at 01:21

I think she converted the barium sulphate into barium carbonate by fusion with sodium carbonate, in order to eventually make the chloride with HCl.

See for instance the following paper which describes a slightly improved variant of the method (utilizing molten NaCl as a solvent to increase the reaction rate):
http://pubs.acs.org/doi/abs/10.1021/ie50466a030

Also, while you are clearly conscious of the potential contamination issues and thinking on how to resolve them, as you should, the problem should not be exaggerated.
I commonly work with small quantities of radioactivily labeled compounds at work and unless you are working with larger quantities or very intensely radioactive compounds it is not very difficult to work with these things safely.
Importantly, continuesly monitor all surfaces etc closely and clean up any spills immediately and thoroughly. Dedicate a certain room or space of the lab to this work and periodically check all surfaces, you, your hands/gloves, door handle etc.
If you conduct your experiments on a very small scale the dose you receive from your experiment will be totally insignificant relative to what you receive from other sources. Fortunately, with the extremely good sensitivity of methods for measuring radioactivity even tiny, unharmful, quantities are easily detected. Consider that many people live in dry, dusty areas with uranium minerals on the surface, and despite many efforts it has yet to be proven that the incidence of cancer is increased in such areas (in fact, current studies appear to show that if anything the risk of cancer is slightly reduced, which may be due to an effect called hormesis).

Ofcouse, while working with radioactive gas /vapor / dust, use a fume hood or other good ventilation.
The thorium nitrate is reasonably dense (around 2.8) which should help against forming airborne dust. You could moisten it with a volatile organic solvent it doesn't dissolve in and evaporate it later to mitigate dust.

[Edited on 16-10-2012 by phlogiston]

annaandherdad - 16-10-2012 at 06:24

I spent some time yesterday looking over the AEC bibliography on literature on radium up to about 1950 that you referred me to. It is amazing to see how rapidly the field developed after the initial announcement in 1898. The papers come fast and furious, developing every aspect of the chemistry and physics of radium and related radioactive substances. I am also impressed by the high quality of the scholarship in those days. It must have been an extremely exciting time to live through. Everyone who did live through it seems to have said so.

I taught a course once on the origins of quantum mechanics, in the period 1870-1910. It was based on a book by Kuhn. I had a similar impression, the scholarship in that era was very high quality. The best people were pursuing the deepest ideas as hard as they could, the best people got promoted and funded (for experimental work). This was mostly in Germany, so it's a reflection on the state of German academics in that period. The early story of radioactivity is more international.

I believe Einstein said that he thought Curie was the only famous scientist he knew who retained her modesty and sense of perspective after achieving fame. Something like that. Hers is an interesting story.

Thanks also for your advice about working with small amounts of radioactivity. My total inventory now is about 80KBq (calculated, not measured). I was of the same opinion as you, that if I were careful, I could work with this without great danger to myself and others. There is an additional worry: I may have to sell my house some day, and I don't want to leave a garage that is contaminated with radioactivity. For a similar reason I don't work with mercury. Spill a small amount, it would splatter and be everywhere, and I'd never get it all cleaned up. Probably no danger to me, since the garage door is open and things are well ventilated when I work there, but what to do when it comes to selling the house? Contamination by thorium nitrate wouldn't be as bad, because I could find it (with a geiger counter), and the total amount of radioactivity is small in any case.

My doctor uses a mercury sphygmomanometer. He says the non-mercury types are crap, they are always getting out of calibration and can't be trusted.

About the effects of small amounts of radiation: Residents of Denver get about 2x as much radiation via cosmic rays as residents of New York. I understand there is no epidemiological trace of this. Also, people in some parts of India get a fair amount of radiation from thorium bearing minerals. Cancer rates do vary from state to state, but I believe it's correct that none of it can be blamed on radiation. But I admit I don't know much about this field (effects of low doses of radiation).

Curie quotes the ranges of alpha particles of various radioactive substances in air, obviously a measure of their energy. It makes me wonder if this can be seen in a cloud chamber. Obviously the source would have to be very thin, to minimize the losses incurred on leaving the source.

She and others talk about deflecting the alphas with a magnet. Nowadays its possible to get very strong permanent magnets. Makes me wonder about things that could be done in a cloud chamber.

I'll read about the conversion of barium sulfate to carbonate, I'm curious how it works.

Thanks also for the very good advice about grinding. If I do it, I'll do it as you suggest.

Doc B - 16-10-2012 at 08:19

I use to work in radiochemical development and production for the federal government and, while i cant vouch for all organisations, we use to send feild staff out to contamined sights and private labs as a matter of course. You may need to develop an premise in order to gain both their attention and cooperation but if you can do so you may be able to pick up some cheap or even free personal dosimetry devices from your local governing nuclear regulator or scientific organization. These will monitor your exposure both whole body (lower limit) and peripheries (higher limit). If you get on well with them they may even lend you the odd contamination device or perform ion chamber measurements etc for you.

watson.fawkes - 16-10-2012 at 08:28

Quote: Originally posted by annaandherdad

Cancer rates do vary from state to state, but I believe it's correct that none of it can be blamed on radiation. But I admit I don't know much about this field (effects of low doses of radiation).

Oh, please. I'm not anti-nuclear, but denying this linkage is just ridiculous. This is from the page Radon and Cancer at the (USA) National Cancer Institute:

Quote:

Radon is the second leading cause of lung cancer in the United States and is associated with 15,000 to 22,000 lung cancer deaths each year.

Radon is an indoor air pollutant associated with the usual suspect mineral bodies nearby. Infiltration is typically via diffusion through foundation walls, generated in subsoils. In some jurisdictions in the US, basement radon venting is mandated by code.

Now, about your sample. A few grams of thorium in a sealed bottle poses no particular risk, as long is it stays sealed in the bottle. Just ensure that any place you work with it can be cleaned.

annaandherdad - 17-10-2012 at 07:28

OK, Watson, let me try to state it more carefully. When I worked with radiation (some time ago), they told us in the radiation safety classes we had to take that there was no epidemiological evidence for increased rates of cancer due to cosmic rays (Denver vs New York, airline stewardesses/pilots versus workers on the ground etc), nor due to the extra radiation from the soil for the people in India who live on top of thorium deposits. They explained that that did not mean there was no effect, but that it was not visible in the large and noisy signal of cancers from all causes.

That was before the hazards of indoor radon were recognized. And yes, it is now believed that many or most lung cancer not caused by smoking is caused by radon (at least that's my understanding of the current situation). As for the rest of it, it still seems to be true that the effects of background radiation cannot be seen in the noisy and not-very-clean data on general rates of cancer. The poor quality of this data allows for different interpretations, which seem to be biased toward whatever political position one wants to take.

One thing seems to be clear: whatever reasonable assumption you make about the effects of low level radiation, it does not begin to explain the large observed cancer rates. Most cancers are evidently not caused by radiation. Nor does radiation explain the substantial differences in cancer rates in different regions (different states). The case of lung cancer in nonsmokers may be an exception.

I have a friend who does research on the effects of radiation on biological systems. The effort is to understand the mechanism(s) by which radiation causes damage, and thereby to give one more to work with when making hypotheses about the effects of low level radiation. I will ask him what his opinion is of the current state of this field.

In the meantime, to return to thorium chemistry, I'm working on some graphs of various activities in the thorium decay chain, as a function of various types of chemical separation, which I will post as soon as I have them.

watson.fawkes - 17-10-2012 at 09:29

Quote: Originally posted by annaandherdad

One thing seems to be clear: whatever reasonable assumption you make about the effects of low level radiation, it does not begin to explain the large observed cancer rates.

That's also true. Radiation is not a general cause of cancer. Radiation from radon is somewhat special, as radon deposits three alphas and two betas per atom directly into the alveolar tissue of the lung after inhalation. There's no shielding the dosage. Ingested radionuclides also are known to cause cancer, though they aren't epidemiologically significant (not since radium manufacture in phosphors was discontinued). There was a particularly egregious case of a radium-containing patent medicine (yes) that killed some by cancer, but more by direct tissue destruction. I've heard stories about workers exposed to plutonium dust getting cancers in their feet, because the particles are so dense they work their way down to the lower point of gravity. This is the real reason to worry about making dust that yields the possibility of inhalation.