Cloud chamber help
I'm not sure where to find advice so I figured this sub could help me. I've been trying to build a cloud chamber and settled on two peltier modules in series between an aluminium plate and a ventirad, with 99.8% IPA evaporated from felt which is heated up by a hot-water bottle.
I didn't check the temperature gradient but guessed it was sufficient since I could observe a nice mist, however there are no ionization traces to be found even after days of trial and error. I made sure the setup is airtight with an insulating foam tape + some additional weight on top, and I also tried using a thoriated tungsten electrode for alpha traces but to no avail (see video).
I tried changing light for contrast but this is the best I could get since this light is directional enough (the flickering is purely a camera effect, also the contrast seems worse on video than to the naked eye). I have this instability in the left part of the chamber, and it seems to originate from a particular side of the lid (if I rotate the lid the instability rotates with it). I think I have some convection currents but I don't know how to get rid of them without destroying the temperature gradient. The transparent lid roughly measures Lxlxh = 10x10x15 cm^3 , maybe I should aim for a 10x10x10 cm^3 ? I tried smaller but got a worse mist overall so I wouldn't go lower.
TLDR: I'm not really sure what the problem is, my guesses are either bad light or bad lid but in any case I don't understand why there no traces at all even with a radioactive object inside the chamber.