Wilson cloud chamber exp. (1 Viewer)

[Gray Shadow]

Or whatever his name is..... just the cloud chamber thing...can anyone give me a brief description of that or just what has that got to do with anything in the course? I know it detects radiation....?? Is it one of the first devices which can detect them using their ionising ability..?

BTW and I want to ask about the discharge tube, does it glow at the anode anyway and the fluorescence material is just to track the whole path... or...??

Thanks for anyone who's willing to help!!

 

[zeek]

Information on the wilson cloud chamber ---> http://en.wikipedia.org/wiki/Cloud_chamber

Discharge tubes glow because the electrons are smashing into some particles along the way to the anode. At relatively high pressures, there is some air left in the vacuum tube, and what happens is that along the way; the electrons hit the air particles and force them to emit energy in the form of visible light. When you decrease the pressure of the tube, less and less air is present in the tube and wat happens is that they "group" up and when the electrons hit them they give out light but this time they form striation patterns. When you decrease the pressure even more till you have a very little amount of air, the electrons can move around freely and sometimes, they miss the anode and smash into the glass behind the anode. When this happens, the silicon dioxide particles in the glass give out green light.
I don't think fluorescent material is added to track the path... it's probably just something that happens because of coincidence, like... it wasn't intended to be there... do u get me?
Discharge tubes "appear" to glow at the anode when there is air in the tube (at high pressures) because the electrons might smash into the air around the anode.