Playing with my self-radiation
May 15, 2019 10:33 AM   Subscribe

I'm going to be taking radioactive iodine in the not distant future to deal with thyroid problems. Are there any sciencey experiments or demonstrations that I can do with my radioactivity, preferably using household items or items that I can acquire for under, say, $50?
posted by donpardo to Science & Nature (11 answers total) 1 user marked this as a favorite
Do you know which isotope? A quick search leads me to guess it'd be Iodine-131 which decays by beta decay which should show up in a cloud chamber. But I wonder if they let you take the radioactive material home.
posted by exogenous at 11:07 AM on May 15 [1 favorite]

One of my former colleagues tells the story of teaching a radioactivity lab right after undergoing such a test, and messing with his students by asking them to hold their Geiger counters up to him.

As noted above, the isotope will affect what sorts of experiments you can do. Iodine-125 is also commonly used for radioactive iodine uptake tests, which is what I assume you're getting. It decays much more quickly and only emits gamma rays, which I suspect would not be visible in a cloud chamber.

But I wonder if they let you take the radioactive material home.

It's stuck in your thyroid until it decays, so I suppose you could bring your neck near the cloud chamber and see what happens. If it's iodine-131, the half-life is a little over a week, so you've got plenty of time.
posted by Johnny Assay at 11:23 AM on May 15 [2 favorites]

Apparently the people that actually know stuff are at work, so I’ll offer my idea: film. If you can find some black-and-white film and tape the container over your thyroid for a while, it should fog the film. According to the always-reliable Wikipedia, ten percent of the radiation is gamma, which will definitely make it out of your body. Ideally you would bracket the exposure by starting with say 5 minutes, then trying next roll with 10, etc. I say this since I have no idea what is a reasonable exposure. Also, if you have a darkroom, you can cut up the film so you’re not wasting a roll for each try. Good luck with the treatment.
posted by Gilgamesh's Chauffeur at 11:29 AM on May 15 [2 favorites]

One of my former colleagues tells the story of teaching a radioactivity lab right after undergoing such a test, and messing with his students by asking them to hold their Geiger counters up to him.

Similar story heard secondhand here, of a prof repeatedly walking by the lab bench to peg the Geiger counter while his new grad student was trying to carefully perform one of their very first experiments using radioactivity.

If you can get ahold of a Geiger counter (if you were in Colorado, I'd offer!), it's often entertaining to test which substances block radioactivity, and to what degree. The type of radioactive decay determines which types of shielding are more or less effective. I believe iodine-131 is beta emitter but a secondary decay event also produces gamma particles. Fun fact: shielding beta emitters with high-density materials like lead can produce bremsstralung (German for "braking radiation"), which we generally want to minimize when choosing shielding materials to reduce radioactivity exposure in a laboratory setting.
posted by deludingmyself at 11:57 AM on May 15 [2 favorites]

Building a cloud chamber sounds like a lot of fun but I wouldn't count on seeing noticeable effects from radioactive iodine inside your body. Perhaps if you get to play with the iodine before you ingest it (probably not) you could see some interesting interactions. Exposing film to your body would probably work, but I can't imagine the end result will be spectacularly interesting.

If you really want to play with radiation, extract the Americium-241 out of an ionizing smoke detector* and use that with a cloud chamber or roll of film or radiac or what have you.

* - Please do not actually do this. It is incredibly stupid to remove the radioactive isotope from a smoke detector and, say, attach it to your leatherman skeletool as a "personal test source" for the radiacs you use at work.
posted by Mr.Encyclopedia at 11:59 AM on May 15 [6 favorites]

If you have access to large-format film and a place to develop it, I would try to see if you can make shapes in it. In a pitch-black room, obviously.
posted by wnissen at 12:53 PM on May 15

The treatment is post-thyroidectomy in order to kill any errant cells, so I strongly suspect it's Iodine-131 . I don't think they'll let me mess with it before I have to consume it.

leatherman skeletool as a "personal test source"
I smell a story.
posted by donpardo at 1:18 PM on May 15 [2 favorites]

Iodine is mostly excreted via urine in case you're adventurous enough to try a cup of pee in a cloud chamber.
posted by exogenous at 2:10 PM on May 15 [1 favorite]

A Geiger counter will allow very interesting demonstrations. Obtaining a working Geiger counter for $50 is possible but tricky. At that price range you'll have to filter out red-herrings (devices that claim to be Geiger counters or are mislabeled as such, but have a cheap sensor instead of a Geiger-Muller tube) so if you're not familiar with Geiger counters you'll probably need to examine your options carefully.

It's quite easy to buy a Geiger counter in the $70-150 range though, if your budget can stretch.
$50 can often get you a used Geiger counter from ebay, and can always buy you a kit that you solder together yourself, etc.
As regards what to look for:
- When looking at a device, try to find specs or information about the Geiger tube. This indicates that there is in fact a tube. (While you're at it, the larger the tube, the better (sensitivity is based on surface area of the interior of the tube, so ideally you want the tube to be at least a couple of inches in one dimension.) It's the heart of the device so information about the tube is part of its basic specs.
- If it doesn't have a battery or power jack, it's not a Geiger counter. (eg dongles that plug into your phone's audio jack are cheap solid-state sensors, not much fun)
- A CD V-700 is an old cold-war Geiger counter. Many still work, good fun. A CD V-715 looks almost the same but is not a Geiger counter - the needle will not move until a nuclear war is melting your face off and causing Geiger counters to fail from too much radioactivity.
- A Geiger tube that reads beta will give you better results, but is fragile. Any dent in the thin metal will collapse it, so avoid handling it unnecessarily directly if you're building a kit. (Normally it's safe inside the device)

Why a Geiger tube? Because they're very sensitive, which is a lot of fun - they will react to your (thyroid) presence in an instantaneous and visceral way. Something cheap might have to sit and count for a couple of minutes, then you move it away and have it count for another couple of minutes, then you compare the two counts and see if there is a significant difference in the number. You can generally connect the audio output of a Geiger counter to an audio jack on a computer or smartphone and run click-counting software, to take extended readings, generate graphs over time, etc.
posted by anonymisc at 12:25 AM on May 16 [3 favorites]

My budget can stretch. I certainly hope this is a one time cost.

CD V-700 is an old cold-war Geiger counter

So this? (Not asking for a guarantee of a particlar listing, but making sure that this is the thing in question.)
posted by donpardo at 6:14 AM on May 16

Yup. That looks decent and it includes the headset which most listings don't. (CD V-700's don't have a speaker, but they have an audio plug, except it's from the 1950s, so the connector which mates with it is the Amphenol 2501F. (Though just wire and glue will do the job...) 3rd-party adapters to make it into a regular audio jack are on ebay, as are the original headsets with the original plug.)

You can get more bang for buck in terms of features from something more modern and plastic, but CD V-700 has that interesting cold-war built-for-apocalypse thing going on, and has the analog needle readout and analog clicks (if connected to something) that are iconic of Geiger counters. CD V-700s were made by several different companies, Victoreen is one of them. Victoreens use 4 regular D-size batteries. (Some manufactures only need 2). They also have a beta check-source on the side of the can, so you can test the probe against it to check it's working. The probe housing has a metal "beta shield" which can be rotated closed if you want to ensure only gamma is being registered. The Geiger tube can detect beta and gamma but not alpha. (A far more fragile, more expensive tube is required for alpha sensitivity, not worth it for your purposes)
posted by anonymisc at 11:55 AM on May 16

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