Saturday, October 25, 2008

Homemade particle physics

It all started with this Making Light thread; Bill Higgins was musing about improvising a radiation detector, which led him to this deeply cool device - scroll down for the cunning methodology that goes with it. But James MacDonald beat him, I think, with this cloud chamber implementation:
Field-expedient cloud chamber:
  1. shot glass.

  2. High-proof vodka

  3. Rubber balloon

  4. Rubber band

  5. Dry ice

  6. Light source

Pour a shot of vodka. Drink it. Do not wipe out glass. Put rubber balloon tightly across mouth of glass, fixing it in place with rubber band. Set glass on block of dry ice. Shine light through side. Pull up on rubber sheet to lower pressure in the shot glass. Observe tracks in the cloud.
And then I saw this story; it turns out that when you rip off sticky tape (that's a scientific term) in a vacuum, there is a discharge of static electricity, so electrons are transferred from one side to the other, and when they strike the tape, they slow down. Energy is of course conserved, so it has to go somewhere, and somewhere in this case is a astonishingly powerful burst of X-rays. This is yer bremsstrahlung, right?

You can probably see where I'm going with this. Now, who sells dry ice in London N19? The spirit, obviously, is no problem. Need to think of a way of arranging to peel off the tape under a vacuum, though.

Hey, it's significantly less crazy than freeze-distilling H2O2, or doing the same thing to Timothy Taylor's Landlord Ale. (You know who you are.)

1 comment:

Dave Cole said...

Attack a piece of string to one end of the tape. Use a motor or linear actuator, connected to a timer or (if you're feeling flash) an IR-operated control circuit. It can be mounted within the vacuum.

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