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I am trying to make a cloud chamber but it does not work yet. I do see a rain effect at the beginning which means that the alcohol is condensing and the rain effect slowly disappears as the vapor gets more saturated. But after that I do not see any tracks at all. I have watched around 30 minutes.

My setup is as following:

  • At the base I have a cooling pack which is frozen in my freezer which is -25°C.
  • On top of that is a black metal fry pan which is also frozen at -25°C.
  • On top of that I have an upside down glass vase sealed with vaseline. On the bottom of the vase I glued filt that I have soaked with 99.9% isopropanol.
  • Then lastly I put a bowl of warm water (around 60°C) on top of the setup.
  • For illumination I use a Black Diamond headlamp which is quite bright.

Video of the rain effect in the first few minutes: https://drive.google.com/file/d/1qxY4sGDQReLlu7NsK4TCh5Z1B--_VaYK/view?usp=drivesdk

Picture of the whole setup (without bowl of warm water): enter image description here

My question is: Does somebody know what I am doing wrong, why it is not working or how I can improve my setup?

Many thanks in advance!

There are a few things I can think of that might possibly cause this problem. Any confirmation or disproof would be appreciated.

  • I live in the Netherlands at around 7 meters below sea level. Maybe there is not enough cosmic radiation at this altitude?
  • Perhaps the humidity/temperature of the room/outside has an effect on the level of relative saturation of the vapor in the chamber.
  • Maybe there is not enough isopropanol evaporating from the filt. This would however be weird as there is quite a lot of rain visible in the first few minutes.
  • Another possibe problem could be the temperature of the bottom plate (currently around -25°C).
  • The light could also be of a wrong type or placed in a wrong way. I do however see the rain effect quite clearly so that would I guess be an indication that the light source is correct. Its currently placed so that it shines horizontally at around 1 cm above the bottom plate. I have also already tried to change the position, rotation and intensity of the light source.
TheCodeGoat
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  • Wellcome, @TheCodeGoat! Very interesting project. One fella did the same thing as a part of his final bachelor's thesis in physics, maybe it is helpful (I am sorry, but it is in Spanish) https://digibug.ugr.es/bitstream/handle/10481/33356/GarciaMartin_CamaraNiebla.pdf?sequence=1&isAllowed=y. I've seen it working using normal ice in the cold reservoir and at the sea level (south of Spain). – Javi Sep 10 '21 at 12:26
  • Thanks for your comment! Do you know if the thesis has a troubleshooting section? – TheCodeGoat Sep 10 '21 at 14:13
  • no, I actually didn't read it. I just saw the chamber working ... Is quite spectacular I might say! Good luck! – Javi Sep 11 '21 at 13:11
  • Hi TheCodeGoat. Linking to private clouds, dropbox, etc, is for various reasons not acceptable on SE, cf. this meta post. – Qmechanic Feb 06 '23 at 10:03

1 Answers1

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I finally got it working. For the people that are still struggling to get it working, I will explain what I have changed in my setup to get it working.

The first thing I did was find a glass cilinder (mine has a diameter of around 20cm) that has two openings, one on either side. Then I have put a metal bowl with hot water on top, and on the bottom side of the bowl I have my felt with alcohol. Now the heat from the water directly transfers to the felt without having to first go through a layer of glass.

The second thing I changed was to use a different cooling pack. I first used a cooling pack with gel used for injuries, however, this becomes solid quite quickly and thus cannot transfer the cold so well. What I used instead was a zip lock bag filled with water that has been saturated with salt (I used 200g of salt in 400mL of water). I then froze that in my freezer (-25°C). Because this stays liquid for a longer time (due to the lower melting point) it can transfer the cold better.

I used this paper: https://www.google.com/url?sa=t&source=web&rct=j&url=https://indico.cern.ch/event/335863/contributions/785342/attachments/1168798/1686802/cloudchamber_salt_ice_mix.pdf&ved=2ahUKEwjhy8bt9Kj5AhXL_qQKHX3OBMYQFnoECAkQBg&usg=AOvVaw2S4Gokf3qX9WL-VYwK-1mD

TheCodeGoat
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