This a 300-watt cloud chamber made with 4 peltier modules, two TEC1-12706 and two TEC1-12715 along with a 12V 29A power supply. Each 15A and 6A peltier are cascaded, giving two cascaded pairs. The two 6A peltier are at the top touching the cold plate and the two 15A at the bottom fixed with the water block. The top peltiers are connected in series to reduce the operating power as to not overwhelm the bottom peltiers, all are clamped together with good amount of thermal grease and insulated with silicone. Then incadesent bulb is just to limit the current for the pumb.

The cold plate can reach -27°C with chilled water as coolant, though it can be even lower with better coolant.

I could not find a radioactive source to test it out properly, but I have managed to show cloud formation with high voltage source (not recomended as the alcohol can ignite)