Protactinium-234m Generator (self-made in the US)

This is a protactinium-234m generator I made myself. It is used in half-life experiments, but they're unavailable in the USA. Protactinium-234m has a half-life of 77 seconds (1.17 minutes). It consists of a three chemicals: Uranyl nitrate (natural or depleted uranium both work), concentrated hydrochloric acid, and methyl isobutyl ketone, which was added to a leakproof 60 mL polypropylene bottle, with an O-ring to help keep it sealed, just in case it were to leak. Protactinium-234m is in the uranium-238 decay series, and is the "granddaughter" radionuclide (or in this case a metastable or "excited" radionuclide) that decays via beta minus decay to uranium-234. It only undergoes isomeric transition about 0.16% of the time to protactinium-234, which has a half-life of 6.7 hours. So, this radionuclide is even more trace. The most common energies (of many) that are emitted by protactinium-234m are a beta particle with an endpoint energy of 2.268 MeV (99.2%) and 1.224 MeV (1%), and many others with mostly lower energies, but only a fraction per decay. There are also many gamma ray energies, however the branching intensities are quite low. 0.83% is the most intense gamma ray emitted per decay, with an energy of 1.001 MeV. X-ray intensities are also fairly low too. Background radiation is about 30-40 CPM, and the protactinium-234m generator gives a reading of about 120 CPM before it is primed.

I use the SEI Inspector USB (v. 2.13) to detect and count the radiation emitted by the protactinium-234m generator. Geiger counters have a very good efficiency for detecting beta particles, so the hard beta radiation emitted is easily detected by the LND 7317 G-M tube that the SEI Inspector USB uses. I used two lucite blocks to keep the detector stationary, a PVC reducer to hold the generator upright and upside down for counting, and a small cardboard box to raise the generator about 2 cm from the G-M detector window. It is also in the proper geometry, which I talk about in the video. The SEI Inspector USB comes with the new Protect Boot, by International Medcom Inc., which has a sliding Plexiglas beta shield door, and a folding magnetic stand (which can't be seen in the video). The newer SEI Ranger has replaced the Inspector USB, and the Protect Boot has replaced the Xtreme Boot for the SEI Radiation Alert-type Geiger counters. This Geiger counter has been calibrated with a NIST-traceable cesium-137 source. It also comes with the free Observer software.

These generators aren't available in the USA, and they're only available to schools in the UK and some other European countries, but I'm pretty sure they're not available to the general public. They also cost a lot! In the UK, they usually cost about 350-450 USD. That's why I made one!

*Correction*: I say "great-grandaughter" isomer. This is incorrect. I don't know how I screwed that one up, but I did. It's the "grandaughter" isomer.

*Disclaimer*: If you do decide to make one yourself, I take no responsibility if you are injured when trying to make one! The chemicals are hazardous! Always take proper precautions! Keep the protactinium-234m generator upright, preferably in another leakproof polypropylene bottle!

[radiumquetzal]

I loved every second! Awesome demonstration, I need to make a similar one sometime.

[Davidparket]

Understood nothing - but very interesting!

[chemistryscuriosities]

Hey Kile, would Methyl, Tertiary Butyl, Ether work instead of the solvent you used? And how much UO2, (NO3) did you add to the 60mL bottle? Great idea! I am going to try running a Gamma spectrum for M Protactinium. Hopefully it works. If it does I will post a video on my channel. Thank you again. Great video

[Maldoror]

Nice! I'll have to make one myself someday.

[Muonium]

Why is the Pa selectively soluble in the relatively non-polar solvent?
....more videos for us soon?

[dakota]

So do you just add Uranyl Nitrate, Hydrochloric acid, and the Methyl Isobutyl Ketone and it just works? or is there a specific procedure

[chemistryscuriosities]

This was an amazing experiment. By the way Autunite can very easily be converted to U, (NO³) if anyone where so inclined to do so. Can you please explain to me how this is working? I'm not understanding why the (m)Pa-234 is only visible to the SEI Inspector USB only after shaking the organic layer and acidic U, (NO³) layer

[chemistryscuriosities]

Can uranyl acetate be used instead of nitrate?

[pkalpha]

Ooo Interesting, did you make your uranyl nitrate yourself?