Exposing radiochromic film with strontium-90 beta particles

Sheets of Gafchromic EBT3 radiochromic film are exposed to radiation from a strontium-90 pterygium eye applicator, causing the dye in the film to polymerize into its characteristic blue form. The influence of a magnetic field is investigated. In total, three sheets are irradiated for one hour each:
1) with no magnet present;
2) with the magnet in one orientation;
3) with the magnet in the reverse orientation.

[@albundy8139]

Glad to see you back Carl, always enjoy a good science experiment on a Sunday!

[@cokeforever]

Please post more often) Loving your channel since your Chernobyl trips with bionerd23, keep them coming!

[@cracktower3613]

🎩 Greetings Carl - at Chernobyl & Hanford you remembered to share with us, . . Even taking time to teach us - no charge! We Love you Sir - Peace always to you & yours 🍀

[@guybaot]

Always extraordinary to see particles interacting with matter.

[@mtitania1975]

Just found your channel a few days ago, love your enthusiasm and the explanations!!

[@Muonium1]

We may only get one video a year from Carl, but it's almost always on something I've never even heard of, let alone actually seen. True to form, I didn't even know such a thing as this kind of film existed. If you started a patreon or something I'd sign up for sure for more regular videos. Are you still selling plasma art?

[@Carl_Willis]

It's pretty hard to do plasma art these days...I have teenagers!

[@stephanieparker1250]

This is what I needed after a long weekend of moving into a new home. (Moving sucks). Thanks for feeding my inner geek. 🎉🎉🎉

[@derekhypes7520]

This was so cool Mr. Willis! To actually see this in real time. Thank you

[@sycksyngyrl]

I Absolutely love how in depth your videos are. You are delightfully meticulous in all of your work. I look forward to seeing more intriguing videos. THANK YOU ❤

[@kcakarevska]

Glad you are back. I've been in deep withdrawal waiting for next video showing me some new thing I'd never heard of.... but should!

[@DirtyPlumbus]

I don't think the average person realizes just how closely tied electricity, magnetism and radio waves really are.

[@EvilScientist]

New upload!! It's been a while, glad to see activity again

[@DrakeLuce]

Lovely experiment!

[@martinsmith3847]

I'm so happy that you're back with another video! Thank you for showing us with detail the source and the box it came in. Can the film also be used to take quick x-rays of things?

[@Carl_Willis]

The film's not exactly "quick." It can form images. Far less expensive to do that with regular x-ray film and a cassette, however. The downside is that regular film requires wet developing and a workflow involving a darkroom (or tent).

[@sacriptex5870]

Your videos are gold! Always very interesting, that source were used to threat eyes with a a condition that make new muscle grew over the cornea causing blindness, so they did a medical removal than apply radiation to prevend any new tissue growth.

[@Carl_Willis]

Thanks for the context. I'm sure some readers will find it useful. My own grandmother had an eye cancer treated with such an applicator at Hammersmith Hospital in the UK in the 1950s, although not one specifically intended to prevent pterygium regrowth.

[@grebulocities8225]

His videos used to be gold, and most of them still are, but a small proportion of them were neutron-activated to gold-198 and then beta-decayed to mercury-198.

[@michaelwall3401]

Thank you for this fun and educational experiment, Carl! Would it be worthwhile (or at least fun) to do something similar with a strong E field and beta? I think it would also fun to "paint" geometries using point (or other) source surrounded by some shielding that has some openings. Maybe even some patterned shielding with different window materials maybe lead, aluminum, and open with a strong beta + gamma emitter to see different exposure effects.

[@Carl_Willis]

Thanks for these suggestions. I agree that a patterned shielding demo would be quite nice!

[@AlbertoMelappioni]

Cool experiment! Thanks for sharing

[@toothless7849]

Bionerd did a video showing how magnetism can effect ionizing radiation YEARS ago. Really cool to see this more in depth, and to actually visualize it! Carl, if there is leftover sheets of film, would it be possible to use them to present and compare the different shielding properties of materials like water, lead, and boron? I tried doing a similar experiment, but with long-exposures of scintillation materials and it didn’t really work out too well.

[@Carl_Willis]

Yep, I think we can do a shielding demo. To make it quantitative, I need to get access to a premium scanner. We'll see what I can do.

[@toothless7849]

@@Carl_Willis Awesome! Thanks, Carl! I’m not really sure where I went wrong in my approach. I’m guessing a sample of americium and a fragment of pitchblende just wasn’t enough when it comes to high energy particles, coupled with aluminum and lead shields. The resulting long exposures were so dim, no comparison could even be drawn between the 4. I find much more comfort in having a trained professional do the experimenting.

[@Travluminatii]

Loved seeing you on the Vice documentary !

[@Carl_Willis]

Very kind of you. I enjoyed that Canadian trip quite a lot.

[@Travluminatii]

@@Carl_Willis I tried emailing you bro. Message me back. I’m making an element price tracker app!!

[@r0b891]

Nice experiment; keep up the neat work.

[@BobDarlington]

Great demo! Thank you Carl.

[@trash0]

Thanks Carl, that's a fun video. You were looking for suggestions for more experiments. I do wonder how the film responds to alpha particles (and neutrons). I was also thinking you might be able to demonstrate some spectroscopy with the film and the magnets. Comparing the A side up and the B side up, the B side has a rather wide spread of particles. I would think I would see bands with specific energies of beta particles for Sr90, if the magnetic field was constant or linear. I'm guessing that in this case it's acting like an unfocused lens and depending on the angle the beta particles enter the magnetic field they are just scattered evenly across the film as they deflect. The question is, can you clean this up and produce a spectrograph where we see a narrow band for 540keV betas and maybe a second band for the Y90 betas. Or changing the source to something with a broader spectrum of beta particles that might show multiple lines. As a rough guess of what I'd try, it would be reducing the beta source through a pin hole filter to get the beam as narrow as possible and then passing it through the magnetic field deflecting the betas as in this experiment. But I'd either try very small powerful magnets right at the exit of the pin hole, or a larger more broad magnetic flux. I can think of several combinations I'd try with my blunt level of experimentation (hit it with a rock science), but I'd probably start with the beam parallel to the film and deflect the betas onto it. A second expirment, aim the beam perpendicular into the film and deflect the betas off the beam line so that all the beta particles have roughly the same distance to travel to the target film. Reversing the polarisation should see a mirror image of the beta spectrum in the opposite deflection. I'd also like to see how the film reacts to a HV electric field. There might be some HV imaging that could be fun too. Of course that leads to demonstrating beta's in electric fields like this experiment instead of magnetic fields.

[@roybm3124]

Amazing video, I have seen this experiment before on KZbin but that didn’t work out. Probably the source was not hot enough. Must be looking beautiful in a Wilson cloud chamber.

[@Carl_Willis]

Probably would be hard to use in a cloud chamber due to the sheer intensity of the cloud nucleation! If I bring a diffusion cloud chamber in the lab I will show what this source does to it.

[@PonteBata]

Awesome! Thanks for sharing! I wonder if there is any similar reaction that can be prepared in a simple chemistry lab?

[@Carl_Willis]

Good idea...I don't know!

[@physgun1]

Cool to see that your posting again Carl! But I have one question, where did you get such a hot strontium source?

[@Carl_Willis]

It's a fairly common type of eye applicator. We have a couple of them at UNM.

[@MinSredMash]

You talk about the the magnets deflected the electrons towards and away from the plane of the paper. But don't they also seem to extend the electrons' overall range in the air?

[@Carl_Willis]

The probability of interaction per length traveled remains the same (just a property of the material--e.g. air--and the radiation type. The magnetic field can cause the electrons to have bent or helical trajectories where they previously would have traveled in a straight line, so if anything, the effective range is smaller.

[@maxbartoshik]

Wow! A very tricky way to get image of USS Enterprise starship. 11:11

[@MikeF1189]

Seems like there could be opportunities for shielding. Space born reactor can shield the crew compartment with strong magnetic fields. How does the magnet effect Gamma and Neutron?

[@Carl_Willis]

Magnetic field probably doesn't do much to gamma rays and neutrons, but may trap their secondary electrons. I like your application idea.

[@MikeF1189]

What about cancer treatment? Maybe you should use magnetic fields to focus treatment

[@MikeF1189]

I wonder what would happen if you had two sources next to each other. Would they set up interference patterns, or would it just be additive.

[@quantumbits]

So Cool!

[@lbochtler]

you could also try exposing sodium and Potassium chloride to beta particles, they are scotophors and will change color when struck with electrons. I have not tested it myself so take the idea with a grain of salt

[@Carl_Willis]

Yes, they make some pretty colors! Need a lot of dose to do it, though.

[@BremsstrahlungChannel]

Maybe try a Double Slit Experiment with Betas or Alphas? :D That Film is really neat stuff! ;)

[@Carl_Willis]

The film is, sadly, coated on both sides with an inactive layer, so that'll limit its utility for alpha particles.

[@greysoulx]

Carl, LTNS! do you think it works be fun to put that strontium source in my pen plotter so you can move the source signs very slowly and produce a drawing of sorts? Would love to get together again, maybe have some more fun with glass and gas!

[@sueuj]

Question- will be scared at first when dealing with radioactive substances after I become a scientist

[@FenianAn1mal]

@Carl Willis what happened at the university reactor? just say the event report you submitted to the NRC.

[@BestSpatula]

So this is the same principle that earth's magnetic field protects us from much of the sun's radiation particles? Do the radiochromic sheets eventually fade back to their original state like photochromic sunglasses do? Thank you for sharing the experiment with the special film, this video was very interesting.

[@Carl_Willis]

Yes indeed. The film will eventually degrade (cosmic rays, other background sources of radiation) and turn dark blue.

[@joshualarson3770]

Love it! See you at Trader Joe’s!

[@fjs1111]

Carl, that is really interesting. Perhaps you could do a video on that chart behind you, that would be great.

[@pedrocrb]

3:57 is it really 47.5cGy/s? that would be 170Gy/h in 1985, or about 70Gy/h today. Is that just at the very surface of the source? It seems way too high so I think I'm doing something wrong

[@among-us-99999]

Is the film gamma sensitive/could it visualize bremsstrahlung?

[@MinSredMash]

Well don't leave us hanging, what were the readings on the Ludlum? And were either of the things on your short a dosimeter? And if so, beta sensitive?

[@Carl_Willis]

Our normal dosimeters (on my shirt) measure shallow dose from beta particles, as well as deep dose. I also am wearing an extremity ring dosimeter that you can see on my finger occasionally in the video. The Ludlum survey meter just reads counts on the Geiger tube, which is pretty much saturated anywhere in direct line of sight from the source. The magnets didn't do anything too nasty to the "beam", it turns out.

[@SerumCRM114]

Would it be possible to use a cathode ray tube to create a specific image on this kind of film? That might be an interesting experiment to perform.

[@Carl_Willis]

Good suggestion! The trick is having electrons with enough energy to penetrate the inactive layer on the film.

[@kevin42]

How'd you get ahold of that source?

[@Carl_Willis]

We have a couple of these at UNM NE. They were in medical use on North Campus before we got them. I just traded out a weaker one for the one you see here, in fact.

[@MagosOfTheLuminary]

Praise The Omnissiah carl is science

[@sunhesunhe4483]

هل من الممكن ان تترجم فيديوهاتك الى اللغة العربية؟