Re: Radon class demo

[Bernard L Cohen <blc+@pitt.edu>]

	Radon and its progeny are distinguished from background by being
mainly alpha emitters. Coat an aluminum foil with fluorescent material
(the type used on screens of TV tubes, cheaply available in pound
quantities) by making a slurry with rubber cement, spreading it on the
foil, and letting it dry. Place it on the face of a photomultiplier
connected to a scintillation electronics system (e.g. unplug the
photomultiplier of a scintillation detector and plug in this
photomultiplier). Your aluminum foil must be thin enough to pass the
alphas. The fluorescent material should be against the photomultiplier
window. Set the discriminator to accept large pulses or feed them into an
MCA, and you will get plenty of signal from radon. By measuring the air
flow (e.g. measuring the time it takes to displace the water in a 1
liter bottle inverted in a water bath), you can determine quantitatively
the concentration of radon progeny in the air ("working level")
	If this sounds complicated, it is not. Anyone could do this in an 
hour or less.

Bernard L. Cohen
Physics Dept.
University of Pittsburgh
Pittsburgh, PA 15260
Tel: (412)624-9245
Fax: (412)624-9163
e-mail: blc+@pitt.edu


On Mon, 27 Sep 1999, Joe Provost wrote:

> Last year a string went out about demonstrations of half life.
> 
> One very interesting idea was to use a vacuum cleaner and an air filter
> (even tissue/toilet paper) to  capture enough radon progeny to not only
> show half-life, but natural
> background, counting limitations, etc
> 
> I tried this using thick filter paper and after 2 min of filtering I did
> not detect any activity over background with a GM counter.
> 
> Any ideas?  I am in the upper midwest and this area should have a pretty
> high conc of radon gas.
> 
> 
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