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Ive been trying to make a cloud chamber for a few days. I seem to have gotten most of the way there, but cant quite see any tracks, only mist. Im using isopropanol with cooling from salted water ice at -18-ish C. I have a metal radiator suspended in the ice as the bottom plate, a glass vase as the container, felt at the top soaked with 99.9% isopropanol and a led laser for ilumination. At the bottom of the container I see a layer around 15 mm thick of isopropanol condensati precipitating slowly. This seems to me to be mostly correct, and I have followed most online tips to ensure the best results, but I have yet to see a track. Any help would be much appreciated. Also I just noticed that over around 10-15 mins the mist starts to become less dense and eventually almost disappears. If I ventilate the container for a few seconds the mist quickly re-appears after that. Video of observation: https://photos.app.goo.gl/XmqVT1kfTfuumW5t8 Isopropanol mist observed in container

The setup

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    $\begingroup$ What’s wrong with my cloud chamber setup? might be of some help. $\endgroup$
    – Farcher
    Sep 4, 2021 at 22:21
  • $\begingroup$ I mean yeah, but im already doing all of the suggestions. There are mostly no convection currents - its just a continuous downward flow $\endgroup$
    – DFined
    Sep 4, 2021 at 23:08
  • $\begingroup$ You can class the downward flow as a convection current! It is important to have the temperature of the base as uniform as possible and you might try and insulate the vertical "wall" at the bottom end? $\endgroup$
    – Farcher
    Sep 5, 2021 at 7:38
  • $\begingroup$ Thanks! Will try to do the insulation bit. And will probably add a thicker metal layer as a heat spreader, the heatsink I use at the moment might have somewhat uneven transfer. But I thought the downward flow is kinda inevitable, right? Even says so in the link you provided - IPA is just heavier than air so it sinks. Though I guess It might be moving too fast $\endgroup$
    – DFined
    Sep 5, 2021 at 9:32

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I am not sure -18 deg C is enough. Maybe you should try dry ice. Maybe you should try to emulate other people's design. See also Near-room temperature DIY cloud chamber?

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  • $\begingroup$ Thanks for the suggestion. I really wanted to avoid dry ice as its not really that easy or cheap to get here, but if nothing else works I will have to try it. I have definitely seen people make chambers with salt water ice and gel ice packs, so I feel like there must be some way to get it working... I guess I should try adding a heat source to the top maybe... $\endgroup$
    – DFined
    Sep 4, 2021 at 20:43
  • $\begingroup$ Also, doesn't the mist mean that its cold enough? Or should there be more? $\endgroup$
    – DFined
    Sep 4, 2021 at 20:47
  • $\begingroup$ @DFined I used dry ice, an inverted plastic fishtank, double felts and methanol. Getting enough mist is really crucial. Using a weak source of radiation, like thoriated TIG electrodes inside the chamber also helps... $\endgroup$
    – Gert
    Sep 4, 2021 at 20:56
  • $\begingroup$ Cool. 👍🏻. Definitely post in engineering too. This might not be the best se. Not sure $\endgroup$
    – Al Brown
    Sep 5, 2021 at 5:49

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