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vmelkon
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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.
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SulfurApothecary
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Beryllium is better than aluminum for neutron generation.
You can't arrest me, it was for science!
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kristofvagyok
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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.
I have a blog where I post my pictures from my work: http://labphoto.tumblr.com/
-Pictures from chemistry, check it out(:
"You can’t become a chemist and expect to live forever." |
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SulfurApothecary
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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.
You can't arrest me, it was for science!
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kristofvagyok
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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]
I have a blog where I post my pictures from my work: http://labphoto.tumblr.com/
-Pictures from chemistry, check it out(:
"You can’t become a chemist and expect to live forever." |
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Lambda-Eyde
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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.
This just in: 95,5 % of the world population lives outside the USA
You should really listen to ABBAPlease drop by our IRC channel: #sciencemadness @ irc.efnet.org
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blogfast25
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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.
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DoctorOfPhilosophy
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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.
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vmelkon
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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.
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unionised
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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.
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Mildronate
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I had Pb gloves and 300mL D2O at home, but i never use.
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Mildronate
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yes also i have xray lamp
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DoctorOfPhilosophy
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Here's an article on neutron activation. The author managed to activate gallium, antimony, europium, bromine, indium, manganese, gold, vanadium,
aluminium, and iodine.
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annaandherdad
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Radon 220 from Thorium
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]
Any other SF Bay chemists?
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phlogiston
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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.
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annaandherdad
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| 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.
Any other SF Bay chemists?
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borrowedlawyer
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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.
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annaandherdad
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| 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.
Any other SF Bay chemists?
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Doc B
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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.
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annaandherdad
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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.
Any other SF Bay chemists?
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watson.fawkes
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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.
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phlogiston
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| 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]
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annaandherdad
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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.
Any other SF Bay chemists?
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phlogiston
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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]
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"If a rocket goes up, who cares where it comes down, that's not my concern said Wernher von Braun" - Tom Lehrer |
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annaandherdad
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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.
Any other SF Bay chemists?
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