Cloud Chamber

Heather, Chris and I built a diffusion-type cloud chamber from items commonly available at Target.

We used:

- polycarbonate food storage container
- block of dry ice
- small baking tin
- shallow plastic tray
- 30 watt HID flashlight
- some wire
- 99% isopropanol
- some paper towels
- a power supply from an ionizer
- a Canon HV20 HD camcorder and an HDMI TV as monitor/recorder
- some black 3M gaffer's tape (NOT duct tape- that stuff is too shiny)
- some bubble wrap to insulate the cold side nicely
- the Am-241 source from a smoke detector (~1 microcurie)

The results were quite good, and the edited highlights are shown here.

Category:

Science & Technology

Tags:

• cloud chamber
• americium 241
• particle trails
• nuclear disintegration

[nkip9230]

Can you still do this while not taking apart a lot of the smoke detector? Im not to sure how my school would feel about a radioactive source that is highly exposed.

[skonkfactory]

@nkip9230 No. Alpha particles don't go through the body of the smoke detector. (In fact, they won't even go through the dead outer layer of your skin- alpha emitters are only dangerous if inhaled or ingested.)

If your school is very worried about such things, you could buy a small piece of uranium ore from United Nuclear, or maybe a TIG welding electrode (some contain thorium, which is mildly radioactive).

[nkip9230]

@skonkfactory I completely forgot about that with Alpha Particles. And considering that they Americium will be in the container....

Im going to see what my physics teacher says. Do you think your design is large enough to catch Cosmic Rays?

[skonkfactory]

@nkip9230 Yes, it catches cosmic rays quite nicely. Most of the tracks in the video are from cosmic rays.

[onthecuttingedge2005]

could you take a piece of glow in the dark material and place it over the 241Americium to see if it excites the Phosphor and causes it to self illuminate, I want to see if alpha is better than beta to self illuminate a glow in the dark object or phosphorescent compound

[skonkfactory]

Why don't you spend the $10 on a smoke detector and try it yourself?

[vmelkon]

@onthecuttingedge2005 I've tried it with the white powder from fluorescent tubes and it works but the glow is weak.

[reubenthorpe1992]

does the ionizer supply the 7.5 kv supply how is it attached via a bolt? btw would a flyback transformer of 7kv be ok

[nkip9230]

I also wanted to ask- was it difficult getting source out of the Smoke Detector?

[kpshc707]

Yes you can but you will need something to magnify it so you can see it unless its a really powerful alpha emitter. i know activated zinc sulfide glows but only from alpha particles.