My brother is a Prof of Neurosurgery and has asked if I can assist him with creating a device to stir a tiny volume of a radio-active solution at 170C. For volume, about 1mL. Because of the radioactivity, he can’t use something like a sonic pulse device.
You could easily use an Arduino as it’s really a timer driving a stepper but the tiny volume, the heat are a challenge. The whole mess is to be enclosed in a radiation proof enclosure.
Gosh ive done a bit of chemistry but ive never been game to work with radioactive solutions.
Concerning the temperature what kind of tolerance do we need? Like +/- 5c or +/- 5×10^-11c?
Concerning the stiring, can we use magnets? Like a labratory magnetic stir bar? Can the solution handle highly magnetic fields? Are there any materials like iron, copper, or aluminium that we need to avoid?
How long is the reaction? If its an overnight reaction can we get power into the chamber or do we need batteries?
This is sooo interesting.
Hope we find a solution.
Pix
Hi Gerard
I think what you might need is a tiny version of those paint (shaker) stirrers like in Bunnings.
Maybe something could be done with one of those small vibrating motors running at a slower speed. The small volume would not be so much of a problem. I could imagine a bit of trouble getting something to “stir” such a small container so if you could shake it …
Cheers Bob
These are the kind of thing I mean.
You use them all the time in chem.
Its usually a ferromagnet coated in some non-reative plastic.
Finding one so small is tough, but they are produced and work great.
I like your idea of shaking. If its an option for reaction id explore that.
Pix
Hi Pix
Yeah. “Plastic coated” would have explained it all. I thought for a bit my Physics teacher at school was leading us astray but it was you all along. Naughty naughty. Forgiven this time ha ha.
Cheers Bob
The device needs to be housed in a radiation-proof enclosure to ensure safety. Select materials that can withstand high temperatures (up to 170°C) and are radiation-resistant. Tungsten and lead are commonly used for radiation shielding.
Hi All
170ºC is pretty hot for any component.
If you go down the shaking path and components that can stand this are not readily available why not shake the whole container assembly
Cheers Bob
At uni we had magnetic stirrers but these were for beaker size non radio-active solutions. For a miniscule 1mL and with regard to safety my thoughts are you need a vibration shaker and perhaps a commercial product can be adapted.
Without being able to see the problem, it’s a bit difficult.
Is it possible to put a motor on the outside of the chamber and magnetically couple it to a wheel inside the chamber? I imagine you’d need something hefty to penetrate the shielding, but that’s just a guess.
Then, from the wheel you can do whatever mechanical coupling you like to spin a smaller magnet that will drive the non-reactive stirrer bar.
One-fifth of a teaspoon, but i still wouldn’t want to put any active electronics inside the chamber.
I definitely wouldnt want to shake the chamber from the outside.
The stresses over time from shaking a box that was not engineered to be shaken would be unacceptable risk if radioactive gear is inside
That isn’t much space to work with below and I wouldn’t think that you’d be able to get a magnetic field for a stir bar through that housing anyway.
Might just be back to the original idea of having a motor driving a small stir rod sitting on top of the unit.
You could look at using a gear system to get the motor away from the heat generating components.
Also depending on the radioactivity of the liquid it may be good having the motor be easily disconnected so the stir rod can b decontaminated easily.
Apologies for the time delay. The Uni crew in San Francisco tried another angle that didn’t work so its back in my court!
I’ve asked to better details as far as dimensions go and am waiting to hear back. I’m thinking along these lines. The tiny blob in the vial is a magnetic bead.
