While trying to build a diffusion cloud chamber using the "classical" Langsdorf method, which employs a cold plate to create a steep negative temperature gradient, inducing supersaturation in alcohol vapour, I have found this interesting alternative from Vollrath (1936) where the authors employ a "chemical method of producing supersaturated vapors".
In particular, they employ the following setup
"a glass jar of rectangular cross section with a cover of porous porcelain. About 50 cc of concentrated hydrochloric acid are placed in the bottom of the jar and a like amount of distilled water is placed on the top of the porous plate. Water vapor diffuses downward from the water and condenses in the acid at the bottom. Hydrochloric acid vapor diffuses upward from the acid and condenses in the water on top. The volume of vapor between the two liquids is supersaturated with respect to both components."
The authors describe such a phenomenon as "isothermal distillation "[that]"continues until both liquids have the same composition."
The authors report such setup to work continously and detect alpha radiation, xrays and cosmic rays for long time. No pictures are present and apparently this technique was not developed because taking photographs was not easy.
I was curious to understand two things here:
What is the physical explanation here for this "supersaturation with respect to both components". I found it a little difficult to understand the meaning of this simple sentence. Can anyone with a physical background better than mine please explain?
Given the physical phenomenon, what could be the rationale to search for less dangerous substances to reproduce this setup? Highly concentrated fuming HCl is really dangerous. The authors report tests with "highly polar vapors" such as "hydrochloric acid-water, nitric acid-water, hydrochloric acid - methyl alcohol, hydrochloric acid - acetone". Sadly, all of these are poisons. Would alcohol like in Langsdorf work?
Did anyone here knew this diffusion cloud chamber setup? Any ideas are welcome!
Thanks
